U.S. Conflict with Iran

U.S. Conflict with Iran

U.S. Conflict with Iran

March 26, 2026 (R48887)
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Contents

Overview

Background: Iran Policy Under the Second Trump Administration

Operation Epic Fury: Status and Objectives

Status of Conflict

U.S. Objectives

Israeli Objectives

Iranian Objectives

Selected Regional and International Impacts

Outlook: Potential Scenarios

Issues For Congress

Summary

U.S. and Israeli strikes on Iran on February 28, 2026, have sparked a wide-reaching regional conflict, with ongoing U.S. and Israeli air operations in Iran and Iranian retaliatory strikes on a range of targets in a number of countries and threats and attacks that have largely halted maritime traffic through the Strait of Hormuz.

In announcing the onset of U.S. strikes, President Donald J. Trump said that the U.S. goal was to "eliminate imminent threats from the Iranian regime." U.S. officials have articulated a number of specific military objectives, including destroying Iran's ballistic missile arsenal and program; destroying Iran's navy; ending Iran's support for terrorist groups; and ensuring that Iran does not acquire a nuclear weapon. President Trump has also framed U.S. and Israeli military action as potentially serving to weaken the regime enough to facilitate its collapse or overthrow by a popular revolt. U.S. and Israeli military strikes appear to have significantly degraded Iran's military; it remains unclear whether there may be circumstances under which the United States might deem key threats from the regime to have been eliminated if the regime itself remains in place in some form.

Iranian leaders (including new Supreme Leader Mojtaba Khamenei, whose predecessor and father Ali Khamenei was killed on February 28) appear to regard this conflict as an existential threat to the regime and Iran has undertaken unprecedented attacks against Arab Gulf neighbors, presumably to put pressure on the United States. Since Iranian threats and attacks on commercial shipping in the earliest days of the conflict, commercial shipping through the Strait of Hormuz has effectively halted, leading to large and potentially compounding disruptions to the global markets for oil, natural gas, and other commodities. Iran's asymmetric capabilities may make opening the Strait to unrestricted commercial traffic by military means challenging. The conflict has also featured attacks by Iran-aligned Iraqi groups on U.S. and other targets and has reignited war in Lebanon, where Israel has initiated major military operations prompted in part by attacks from Hezbollah. The conflict raises longer-term questions about the future of U.S. policy in the Middle East, where other governments in the region, including those with which the U.S. has partnered, may weigh the potential benefits of continued or enhanced cooperation with the United States (including to contain or combat Iran) against the potential for retaliation, economic disruption, and domestic uncertainty that may be associated with future U.S. and/or -Israeli confrontations with Iran.

Potential outcomes to the conflict include the following possible scenarios, which are not necessarily mutually exclusive:

Uneasy Ceasefire. Because of economic or other pressures, as well as the considerable damage already inflicted on Iran and throughout the region, U.S. and Iranian leaders could conclude that the cost of continuing military action bears diminishing returns and decide to cease active hostilities without broader agreement.

Negotiated Settlement. U.S. and Iranian leaders had previously appeared to support efforts to reach a negotiated settlement on issues of longstanding U.S.-Iran dispute, and at times during the current conflict have expressed some support for an accord favorable to their respective goals. It is possible that one or both sides could assess at a certain point that their interests are better served by a formal agreement, rather than by continued military action.

Expanded Military Action. U.S. leaders could expand military operations. The nature, scope, and implications of such a scenario could vary depending on whether U.S. or other forces decide to extend or expand the volume of strikes or types of targets selected, or whether the United States or others introduce ground forces or attempt to displace and occupy some portions of Iran's territory.

Fall of Iranian Government. U.S. and Israeli military action, including the killing of senior Iranian leaders and the destruction of some infrastructure associated with the regime's domestic security apparatus, could create conditions more favorable to the collapse of the Islamic Republic. The fall of the Islamic Republic could lead to multiple outcomes, including a new government or a more chaotic situation.

Depending on the course of the conflict, including the scenarios outlined above or parts of them, Congress may assess U.S. national security priorities and deploy various legislative and oversight tools to support, reject, or seek to modify the Administration's approach to Iran and the region. Present and potential future issues for Congress include proposed U.S. arms sales to regional partners; supplemental appropriations; the restriction or authorization of the use of U.S. military force; oversight of possible negotiations and resulting agreements; U.S. sanctions on Iran; and U.S. assistance for entities inside Iran or elsewhere in the region.

Overview

U.S. and Israeli strikes on Iran on February 28, 2026, have sparked a wide-reaching regional conflict, with ongoing U.S. and Israeli operations in Iran and Iranian retaliatory strikes on a range of targets in a number of countries and threats and attacks that have largely halted maritime traffic through the Strait of Hormuz.

If the Islamic Republic endures, the United States may balance the costs, benefits, and risks of various options, including (1) negotiating a deal that includes an end to hostilities and potential policy concessions by Iran, the United States, or others; (2) concluding or suspending hostilities as part of an uneasy, informal, or temporary ceasefire; or (3) escalating U.S. military action. The fall of the regime, as part of a popular uprising or a collapse for other reasons, could yield differing advantages and challenges for the United States and its regional partners. Issues and questions for Congress may vary under different scenarios.

Background: Iran Policy Under the Second Trump Administration

A month after returning to office in 2025, President Trump signed National Security Presidential Memorandum 2 (NSPM-2), which directed U.S. officials to impose "maximum pressure on Iran" (via sanctions, diplomacy, and legal action) to compel Iran to abandon its nuclear program and its support for terrorist groups.¹ President Trump also stated that month that he would "much prefer a Verified Nuclear Peace Agreement" with Iran over military action.² On April 12, 2025, U.S. and Iranian diplomats met for the first such reported engagement in nearly three years. In five rounds of mostly indirect talks in April and May 2025, negotiations appeared to center on Iran agreeing to potential restrictions on its nuclear program in exchange for the United States agreeing to reduce sanctions pressure on Iran.³

12 Day War.⁴ On June 13, 2025, two days before U.S. and Iranian diplomats were scheduled to meet for a sixth round of talks, Israel began a major military operation against Iran, including air strikes and reported covert action. Iran retaliated by launching waves of ballistic missiles against Israel. The United States initially said it was not involved in the Israeli attack, and was prioritizing the safety of U.S. forces in the region. President Trump subsequently indicated greater U.S. alignment with Israeli operations, writing that "We now have complete and total control of the skies over Iran" and calling for Iran's "unconditional surrender."⁵ On June 22, the United States carried out air- and sea-launched strikes on three nuclear facilities in Iran in an operation that U.S. officials said afterward "was not and has not been about regime change" and was "very narrowly tailored" to "destroy or severely degrade Iran's nuclear program."⁶ On June 23, Iran launched a retaliatory missile attack against Al Udeid Air Base in Qatar, where U.S. personnel have been based; no casualties were reported. Hours later, President Trump announced that Israel and Iran would end hostilities on June 24, bringing what he termed the "12 Day War" to an uncertain conclusion.⁷

December 2025-January 2026 Protests.⁸ In December 2025, anti-government demonstrations focused on economic grievances broke out in Tehran, with protesters subsequently taking to the street in cities throughout the country. The Iranian government responded with a violent crackdown that surpassed its repression during past instances of popular unrest, killing thousands and arresting tens of thousands more. President Trump said in early January he was considering intervening to "rescue" protestors and that "HELP IS ON ITS WAY"; popular unrest was largely quashed by mid-January.⁹

Operation Epic Fury: Status and Objectives

President Trump directed a buildup of U.S. military forces near Iran from late December 2025 through late February 2026. On February 28, 2026, U.S. and Israeli forces began striking targets in Iran, initiating Operation Epic Fury (United States) and Operation Roaring Lion (Israel).

Status of Conflict

As of March 26, the conflict has proceeded on two parallel but related tracks.

On the U.S. and Israeli side, missile and airstrikes against Iranian targets continue, with an estimated 50,000 U.S. service members deployed "in and around the Middle East."¹⁰ As of March 25, U.S. Central Command (CENTCOM) reported that the United States has struck over 10,000 targets in Iran, including missile and drone sites, Iranian naval assets, Iran's military industrial base, and command and control centers associated with the Iranian military and the Islamic Revolutionary Guard Corps (IRGC).¹¹ U.S. officials say those strikes have resulted in the U.S. establishment of "air superiority over vast swaths of Iran" and the destruction of much of Iran's regular naval surface fleet.¹² U.S. military officials also claim to have destroyed much of Iran's missile manufacturing capabilities.¹³ Israeli strikes appear to have focused largely on the Iranian regime: Israel has killed Supreme Leader Ali Khamenei (in office since 1989) and dozens of other senior Iranian military and political leaders, and hit a range of targets associated with the Iranian regime's military infrastructure, including those belonging to the IRGC, Basij paramilitary forces, and other security branches.¹⁴

As the United States and Israel continue to use mostly air power to degrade Iran's military capabilities, there have been instances of civilian casualties. On February 28, a Tomahawk missile reportedly hit a school in Minab, Iran and killed 168 people, mostly children; a preliminary U.S. military investigation reportedly determined that the United States was responsible and had used outdated targeting information. On March 11, 46 U.S. Senators wrote to the Administration requesting answers about the bombing, rules of engagement, possible use of artificial intelligence, and other information about civilian harm mitigation measures.¹⁵

Conflict Casualties and Cost of U.S. Military Operations

As of March 23, 13 U.S. service personnel officially have been reported killed in Operation Epic Fury. Israel has reported 3 soldiers killed (and 16 civilians) and France has reported 1 soldier killed. At least 4 soldiers in countries comprising the Gulf Cooperation Council (GCC) have been reported killed along with more than 20 civilians. On the other side of the conflict, there have been more than 3,000 fatalities reported in Iran and more than 1,000 reported in Lebanon.¹⁶

On March 12, 2026, the New York Times reported that "Pentagon officials" briefed Members that the estimated cost of Operation Epic Fury "exceeded $11.3 billion in the first six days," although this figure "did not include many of the costs associated with" the operation.¹⁷ Nongovernmental organizations have also offered cost estimates for the operation.¹⁸

As of March 26, the Administration has not made a formal request to Congress for supplemental assistance, though House Speaker Mike Johnson has said that such a request is "inevitable."¹⁹ According to media accounts, the Pentagon has requested White House approval for a $200 billion supplemental request. A supplemental bill could address munitions replenishment (for U.S. as well as partner military forces), replacing lost equipment (including radars and air defense interceptors), fuel costs, and servicemember pay, amongst other things.²⁰

One focus of ongoing and possible future operations has been energy infrastructure in Iran and the Gulf region. After a March 10 Israeli strike on fuel depots near Tehran, U.S. officials reportedly directed Israel to refrain from targeting Iranian energy infrastructure.²¹ On March 13, the United States reportedly carried out strikes on military targets – rather than civilian energy infrastructure – on Iran's Kharg Island, through which 90 percent of Iran's oil exports have transited. A March 18 Israeli strike on an Iranian natural gas production facility (which the United States may or may not have known about or approved in advance) led to retaliatory Iranian attacks on energy sites in Qatar and Saudi Arabia. On March 21, President Trump threatened to "obliterate" Iran's power plants within 48 hours if Iran "doesn't FULLY OPEN, WITHOUT THREAT, the Strait of Hormuz."²² Iran responded with vows to attack regional energy sites, after which President Trump stated that he had postponed strikes on Iranian power plants and energy infrastructure because of "GOOD AND PRODUCTIVE CONVERSATIONS;" days later he stated he was "pausing the period of Energy Plant destruction by 10 Days to Monday, April 6, 2026," again citing ongoing talks. ²³ Iran publicly denied engaging in such conversations.

On the Iranian side, Iran has launched hundreds of missiles and thousands of drones across the region, with two apparent main lines of effort:

Attacks on sites in Israel and the Gulf Cooperation Council (GCC states), with over 40% of missiles and drones aimed at the United Arab Emirates (UAE) alone.²⁴ Iran claims that its attacks target Israel and U.S.-related sites, such as military bases where U.S. forces are present and U.S. diplomatic facilities. Target countries have reportedly intercepted the vast majority of missiles and drones, but some have evaded air defenses, causing casualties and damaging infrastructure.²⁵ For example, Iranian missiles caused civilian injuries in southern Israel near Israel's Dimona nuclear facility on March 22. Iranian attacks have reportedly caused some damage at U.S.-related sites across the region, rendering some "all but uninhabitable."²⁶ In response, the State Department has directed the departure of some staff from most embassies in the region, suspended operations at several diplomatic sites, and coordinated U.S. government-facilitated departure options for U.S. citizens wishing to depart the region.²⁷

Attacks on commercial shipping, which have led to a massive decrease in shipping traffic through the Strait of Hormuz and increases in global oil and natural gas prices.²⁸

The U.S. intelligence community has also reportedly warned that the Iranian regime could target U.S. firms with cyberattacks; an Iran-linked hacking group reportedly claimed responsibility for a "destructive" March 11 cyberattack on the U.S.-based medical technology company Stryker.²⁹

U.S. Objectives

When President Trump announced the onset of U.S. strikes on February 28, he cited the long history of antagonism and hostility between the United States and Iran going back to the 1979 Iranian Revolution, which overthrew the U.S.-backed Pahlavi family monarchy and replaced it with the theocratic system of today's Islamic Republic. Referencing Iran's support for terrorist groups, its missile and nuclear programs, and other longstanding issues of U.S. concern, President Trump said, "we're not going to put up with it any longer" and said that the U.S. goal was to "eliminate imminent threats from the Iranian regime."³⁰

Trump Administration officials have consistently said that U.S. operations are aimed at eliminating Iranian military capabilities, specifically Iran's ballistic missile program and its navy, as well as ending Iran's support for terrorist groups and ensuring Iran cannot have a nuclear weapon.³¹ President Trump has at times posited a more expansive objective of facilitating regime change by weakening the Islamic Republic so much so that the Iranian people are able to "take over your government," as he said on February 28. It remains unclear whether there may be circumstances under which the United States might deem key threats from the regime to have been eliminated even if the regime itself remains in place in some form.

A prominent short term U.S. objective appears to be reopening the Strait of Hormuz to commercial traffic, though the United States' ability to do so militarily may be limited, as President Trump stated on March 14, writing "it's easy for [Iran] to send a drone or two, drop a mine, or deliver a close range missile somewhere along, or in, this Waterway, no matter how badly defeated they are."³² President Trump's stated views appear to have shifted from an initial suggestion that the United States would have the primary role in keeping Hormuz open, writing on March 20 that the "Hormuz Strait will have to be guarded and policed, as necessary, by other Nations who use it – The United States does not!"³³ Iran has continued its own oil exports through the Strait during the conflict (Treasury Secretary Scott Bessent said on March 16, "we've let that happen to supply the rest of the world") and has reportedly permitted safe passage to some vessels, though most traffic remains halted.³⁴

Israeli Objectives

Before the conflict, Israeli officials advocated for the Trump Administration to adopt objectives for Iran beyond countering its nuclear program, to encompass degrading its missile arsenal and production capacity, as well as reducing Iran's regional sway with armed groups.³⁵ Early in the conflict, Israeli Prime Minister Benjamin Netanyahu repeatedly called on the Iranian people to rise up and topple the Islamic Republic.³⁶

After the first week of the war, Israel appears to have updated its messaging on regime change in Iran, perhaps preparing for the possibility that an Iranian domestic uprising—if one occurs—could take place over a longer timeframe or at some point after U.S.-Israel military operations cease.³⁷ Israeli leaders have indicated that they may target new Iranian Supreme Leader Mojtaba Khamenei or other regime figures as part of Israeli efforts to "create the conditions" for some form of domestic transformation in Iran.³⁸

Iranian Objectives

The Iranian regime likely sees this conflict as an existential threat. With the regime having apparently withstood initial U.S. and Israeli attacks without collapsing, Iranian leaders have said that they have no intention of ending attacks until their own objectives are met.³⁹ That could mean Iran seeking to continue operations until the extraction of tangible concessions, or until Iranian leaders assess that they have imposed such costs that the United States and Israel will not again choose to initiate conflict in the coming months or years.

As of March 25, Iran retains some ability to impose costs, despite the considerable damage inflicted on its overall power projection capabilities by the United States and Israel. Because Iran's ability to directly threaten U.S. and Israeli targets is relatively constrained, Iranian leaders have apparently decided to put pressure on the United States via attacks on longtime U.S. partners in the Gulf and via the global economic disruptions caused by those attacks and threats to maritime transit in the Strait of Hormuz. Iranian missile and drone attacks have caused enough damage throughout the Gulf to force energy producers to halt oil and gas production and exports. Iran's continued ability to launch small, low-cost drones and to threaten Gulf shipping via mines and/or small seacraft has effectively closed the Strait of Hormuz and may have a greater impact on energy resources, and be harder for U.S. forces to eliminate, than Iranian capabilities the United States has targeted thus far such as its missile program and surface fleet. Some observers have described the conflict as a war of attrition between Iran's likely decreasing ability to continue attacks and the possibly finite capacity of the United States and partners in the Gulf and Israel to counter and bear the military, social, economic, and political costs of those attacks.⁴⁰

Iran is in a period of transition, with a possibly injured Mojtaba Khamenei selected on March 8 to succeed his father as Supreme Leader amid debate about what his elevation portends for the future policy direction of the Iranian government.⁴¹ The regime could assess that an end to conflict would give it necessary space to begin reconstruction and solidify itself at home; alternatively, it could conclude that a continued war of national defense or some form of continued low-level conflict would buttress its position.

Selected Regional and International Impacts

On March 2, 2026, the Iran-backed group Lebanese Hezbollah began firing into northern Israel, prompting large-scale Israeli military operations in the country. Hezbollah suffered major losses in fighting with Israel between October 2023 and a November 2024 ceasefire, after which some Israeli military operations in Lebanon continued in parallel with a multi-sided debate over ceasefire compliance. Citing those operations as well as Khamenei's death, Hezbollah restarted its attacks against Israel. The Lebanese government has taken the unprecedented step of banning Hezbollah's military activities, though the Lebanese Armed Forces (LAF) chief's reported inability and/or unwillingness to enforce the decree has sparked political contention.⁴² Lebanon's president has appealed, apparently without success, for direct talks with Israel to end the conflict. Amid the current conflict, Lebanon's parliament voted to delay national elections initially scheduled for May 2026 for two years.

Israeli operations in Lebanon (which reportedly have displaced one million people, or about 20 percent of the country's population) seek to reduce the ability of Iran and its allies to threaten Israel from Lebanese territory. Israeli objectives may include the creation of an even larger buffer zone in southern Lebanon to reduce Hezbollah threats to Israel, and the exertion of pressure on Lebanon's government and military to marginalize Hezbollah—both politically and militarily—and disrupt the group's sources of weapons and funding. The history of Israeli involvement in Lebanon over several decades suggests that any short-term gains for Israeli security could engender popular domestic resistance over the longer term to a prolonged Israeli presence in Lebanon and/or any Lebanese political decisions deemed to be driven by Israeli demands.

Iraq finds itself in a familiar, if intensifying predicament, caught between warring parties and serving as both a venue for and source of attacks at what was already a sensitive domestic political moment. During the current conflict, Iraq has seen strikes on bases housing U.S. and coalition personnel in the Kurdistan Region of northern Iraq, U.S. diplomatic facilities in and around Baghdad, oil tankers in Iraqi waters, and personnel associated with Iranian-aligned groups. The conflict may affect the outcome of negotiations to form a government following Iraq's November 2025 elections. Iran-aligned groups are now demanding the full expulsion of all foreign forces from Iraq.⁴³ U.S. forces were set to continue their drawdown from Iraq during 2026 under a bilateral agreement, but the future of those forces, their mission in pursuing Islamic State remnants in Syria, and U.S.-Iraqi security ties may look different in the shadow of U.S.-Israeli conflict with Iran.

The conflict has focused some attention on the stance and potential involvement of Russia and China. In some ways, Iran's relations with these U.S. rivals have advanced in recent years, underpinned by Iran's provision of drones to Russia for use in Ukraine (Ukraine has offered its expertise in counter-drone defense to the GCC states) and increased Iranian oil exports to China. Both countries have condemned U.S. operations and acknowledged Iran's new Supreme Leader.⁴⁴ There are some indications that Russia and China may find advantages in the conflict: Russia has reportedly provided Iranian forces with target intelligence and advice on drone tactics; Russia also benefits from increased oil prices and the Trump Administration's March 5 and March 12 general licenses authorizing the otherwise sanctionable delivery of Russian crude oil to India.⁴⁵

China has been the destination for the vast majority of Iran's oil exports in recent years. Iran has reportedly continued to send its oil through the Strait of Hormuz since the conflict began, with exports exceeding an average of 2 million barrels a day in early March. President Trump said that potential U.S. action to reestablish free movement of energy through the Strait of Hormuz would be a "gift from the United States of America to China," later writing that China and other countries "Hopefully … will send Ships to the area."⁴⁶ Both China and Russia abstained from the March 11 vote on United Nations Security Council Resolution 2817, which condemned Iran's "egregious attacks."⁴⁷

The conflict could also have considerable global macroeconomic impacts, with some analysts warning that its continuation, in particular the disruption of shipping through the Strait of Hormuz, will have effects well beyond energy markets. In a March 12, 2026, report, the International Energy Agency (IEA) said the current conflict is "creating the largest supply disruption in the history of the global oil market," with the flow of oil through the Strait decreasing by 20 million barrels per day and Gulf producers cutting production by at least 10 million barrels a day; disruptions to natural gas may be even greater.⁴⁸ One March 22 analysis concluded that even if hostilities concluded immediately, it could take four months for energy markets to return to normal.⁴⁹ Additional risks include disruptions to the supplies and prices of commodities like helium (one-third of which comes from Qatar) and aluminum (Qatar and Bahrain have accounted for 8% of the world's aluminum supply).⁵⁰ The Gulf is also a key source of inputs for fertilizer production such as natural gas, urea, and sulfur; increases in the prices of these commodities could have more general impacts on agriculture.⁵¹ The United Nations has stated that increased energy and fertilizer costs could "could leave millions of families priced out of staple foods, particularly in import-dependent countries, like [in] sub-Saharan Africa and Asia."⁵²

Outlook: Potential Scenarios

Outcomes of the U.S.-Iran conflict and its repercussions are uncertain. The following analyses explore some, but not all, of the potential scenarios that may arise; these scenarios are not necessarily mutually exclusive.

Uneasy Ceasefire. Because of economic or other pressures, as well as the considerable damage already inflicted on Iran and throughout the region, U.S. and Iranian leaders could conclude that the cost of continuing military action bears diminishing returns and decide to cease or suspend active hostilities without broader agreement.

Under such a scenario, for the United States, Iranian capabilities might be sufficiently degraded that they are deemed no longer an imminent threat to U.S. forces or partners; for Iran, the demonstration of its abilities to endure and to disrupt the global economy may be deemed more valuable than continued attacks, especially if continued or expanded attacks were to further alienate or antagonize Iran's Gulf neighbors and global energy consumers. In this case, U.S. objectives might diverge from those of Israel, which appears more set on destabilizing the Iranian government and durably reducing the ability of any armed groups in Iran to project power beyond its borders.

In an uneasy or temporary ceasefire scenario, U.S. partners may weigh the potential benefits of continued or enhanced cooperation with the United States (including to contain and combat Iran) against the potential of retaliation, economic disruption, and domestic uncertainty that may be associated with possible future U.S.-Israel confrontations with Iran. Within the GCC, commentary from some observers and officials suggest varying degrees of frustration with Israel and the United States for initiating strikes against the public advice of the GCC states and outrage with Iran for undertaking strikes against nonbelligerent states. Depending on the extent to which Gulf officials share such views and the impact they see U.S. policies having on the security of the GCC, its infrastructure, and adjacent waterways, they may reconsider the nature and extent of their partnership with the United States. Gulf states could decide to encourage or support extended or more aggressive U.S. operations or engage in operations against Iran themselves, but presumably would weigh potential retaliation costs before doing so.

An uneasy or temporary ceasefire could motivate GCC states to deepen their mutual ties and their ties to the United States or others out of necessity, especially if Iran sought to coerce the GCC states through continued threats of attack or disruption of maritime transit. A weakened but coercive Iran could pose challenges to the security of the GCC states and the viability of their various economic and social transformation initiatives. Intermittent and/or low-level conflict could also persist under such a scenario and entail additional costs for the United States and Israel. Some analysts have pointed to possible parallels between the current situation and the standoff and recurring crises that ensued between the United States and Iraq after the 1991 Gulf War.⁵³

Negotiated Settlement. U.S. and Iranian leaders had previously appeared to support efforts to reach a negotiated settlement on issues of longstanding U.S.-Iran dispute, and at times during the current conflict have expressed some support for an accord favorable to their respective goals; President Trump stated on March 24 that Iranian leaders "want to make a deal so badly."⁵⁴ It is possible that one or both sides could assess at a certain point that their interests are better served by a formal agreement, rather than by continued military action. The content and sustainability of such an accord may be shaped by the extent to which it includes or considers the interests of other countries in the region, especially the Arab Gulf states, Turkey, and Israel.

If the Iranian government concluded that it was unable to sustain itself under continued or expanded military pressure, then Iranian leaders could be prepared to make concessions, including with respect to its nuclear, missile, and regional activities. The prospect of additional or more coordinated pressure from other parties, either economic or military, might also motivate a more conciliatory Iranian approach to some issues. At the same time, the United States might also be prepared to negotiate some of its stated goals with respect to Iran and its military capabilities in order to secure the free flow of energy resources through the Strait of Hormuz. Under such conditions, Iran could seek sanctions relief and/or restitution for damages caused to Iranian infrastructure during the conflict.

Iranian flexibility and accommodation of U.S. and regional parties' interests now may depend on Iranian leaders' perceptions of their government's prospects. For example, a weakened but enduring Islamic Republic government could seek later to increase its influence in Iraq and demand the expulsion of U.S. forces, creating the possibility of confrontation and conflict with U.S. partners in Iraq. Similarly, such a weakened but enduring Islamic Republic may strive to affect developments in Lebanon.

Expanded Military Action. U.S. leaders could seek to expand military operations. The nature and implications of such a scenario could vary depending on whether U.S. or other forces decided to extend or expand the volume of strikes or types of targets selected, or whether the United States or others introduced ground forces or attempted to displace and occupy some portions of Iran's territory. Sustained attempts to remove the Islamic Republic government through military force could entail commitments of personnel and resources with uncertain prospects. To date, President Trump does not appear to have ruled out the use of U.S. ground forces within Iran.

Potential targets for expanded military operations may include Iran's stockpile of highly enriched uranium (HEU), Kharg Island, and Iranian coastal areas along the Strait of Hormuz.⁵⁵ Since mid-March, the Pentagon has reportedly ordered the transfer of "an element of an amphibious ready group and attached Marine expeditionary unit" as well as combat forces from the U.S. Army's 82nd Airborne Division to the Middle East.⁵⁶ Some reports have indicated the Administration has also considered material support to Iranian Kurdish groups to weaken the regime.⁵⁷

Expanded military operations could trigger new Iranian responses, given that Iranian leaders have acted on promises to follow the United States and Israel up the so-called "escalation ladder," matching attacks on Iran with Iranian attacks on what they regard as analogous targets abroad. For example, Iran launched a new attack against Qatar's Ras Laffan LNG plant after Israeli strikes on Iranian natural gas infrastructure. Iranian forces may be more able (and motivated) than they have been to date to successfully strike closer targets, such as U.S. ground forces within Iran, U.S. vessels immediately off Iran's coast, and targets in neighboring countries. Iran-backed groups in Lebanon, Iraq, and Yemen also could respond differently or more forcefully to expanded military operations against the Islamic Republic. During the current conflict, Yemen's Houthi movement (Ansarallah), which from 2023 to 2025 targeted Israel and international shipping in the Red Sea, has not struck Israel or targets in neighboring waters and countries.

Expanded military action intended to force or facilitate the removal of Iran's regime could entail costs that impose tradeoffs relative to potential U.S. security needs in other global contingencies, and increase perceived risk among some U.S. strategic planners of coordinated or opportunistic conflicts in other theaters. The enduring military defeat or removal of the Islamic Republic as a longtime U.S. adversary similarly could allow the United States and its partners greater freedom of action in the Middle East and beyond. Whether or not that would provide greater assurance to global consumers of Gulf energy and related commodities is uncertain at this time.

Fall of Iranian Government. U.S. and Israeli military action, including the killing of senior Iranian leaders and the destruction of some infrastructure associated with the regime's domestic security apparatus, could create conditions more favorable to the collapse of the Islamic Republic. The fall of the Islamic Republic could lead to multiple outcomes, including a new government, which may or may not be more favorably disposed to the United States than the Islamic Republic.

The rise of a new government in Iran could yield strategic benefits for the United States and its partners: the removal of a decades-long adversary could free up U.S. and partner resources for use elsewhere that have been long dedicated to countering the Islamic Republic. The nature and posture of a post-Islamic Republic Iran would determine the extent of such benefits.

The fall of the current government could result in broader dysfunction, to include the collapse of central authority in Iran. Under such a scenario, whether or not the Islamic Republic continues its nominal rule, neither it nor another entity would be capable in the short term of extending its writ across the country. IRGC remnants, regime opponents, ethnic minority-oriented groups, and other powerbrokers could all struggle for control, perhaps with the involvement of outside powers or other entities. An Iran deprived of the ability to project power throughout the region could satisfy Israeli goals and result in Israel—which has faced political and economic challenges from mobilizing military reserve forces for multiple combat areas since the Hamas-led attacks of October 7, 2023—considerably reducing the level of personnel and resources it has committed to forward positions near its borders. However, such a scenario could pose potential risks for the United States and some regional partners such as the GCC states, Iraq, Turkey, and Pakistan, including mass displacement and migration flows, the proliferation of weapons and nuclear material, and extremism in ungoverned spaces.

To date, the apparent dissatisfaction many Iranians have with the regime has not resulted in anti-regime protests during the current conflict, and regime forces appear to retain the will and ability to deter and confront domestic opponents. However, if U.S. and Israeli military action limits the ability of regime members to mount an organized repression campaign, then groups opposed to the Islamic Republic would be more likely to pursue opportunities to challenge its authority. Under such circumstances, underlying social and political conditions in Iran and the experiences of other regional countries in recent years suggest that questions of leadership, organization, and political competition would shape the prospects of any movement to displace the regime. Contenders for power may arise from within the country or from components of the exiled Iranian diaspora. Civil conflict could result from resistance to the regime or because of opposition rivalries. Covert or public U.S. support, whether rhetorical and/or material, to certain regime-opposed Iranians could empower them vis-à-vis the regime or could discredit them in the eyes of other Iranians. At this time, there does not appear to be organized, broad-based political and/or armed opposition inside Iran presenting an identifiably clear threat to the regime.

Issues For Congress

Depending on the course of the conflict, including the scenarios outlined above, Congress may assess U.S. national security priorities and deploy various legislative and oversight tools to support, reject, or seek to modify the Administration's approach to Iran and the region.

Arms Sales. Since the conflict began, the Trump Administration has notified Congress of its intent to sell more than $23 billion in arms to Israel, Kuwait, Jordan, Qatar, and the United Arab Emirates, mostly as part of emergency arms sales that bypass the standard congressional review process. Senator Bernie Sanders has introduced three resolutions of disapproval to block notified emergency arms sales to Israel (S.J.Res. 136; S.J.Res. 137; S.J.Res. 138). Going forward, Congress could consider whether to authorize, prohibit, or condition additional arms sales to replenish or expand Gulf state, Israeli, or other partner capabilities (including interceptors and other air defense components) against a depleted but still threatening Iranian government. Proposed arms sales could also focus attention on the broader issue of industrial base capacity.

Appropriations. As noted above, U.S. military operations over the first week of the conflict may have entailed the expenditure of billions of dollars in munitions alone, and, according to media accounts, the Pentagon has presented to the White House a request for a $200 billion supplemental. Beyond a potential FY2026 supplemental appropriations or reconciliation bill, work on FY2027 appropriations presents Congress with opportunities to shape U.S. action toward Iran: Congress could enable, condition, or prohibit the use of funds for various purposes, or could appropriate additional funds to cover the cost of ongoing operations and/or in anticipation of future operations. Expanded or extended U.S. military action would likely entail greater costs and could result in supplemental appropriations requests from the Administration.

Authorization for Use of Military Force. Congress could consider, via the War Powers Resolution (P.L. 93-148) or other legislative vehicles, whether or not to authorize, prohibit, or condition the greater application of U.S. military force, including the use of U.S. ground forces on Iranian territory. Measures to approve or consider joint resolutions directing the removal of U.S. armed forces from hostilities with Iran were rejected by the House (on March 5) and Senate (on March 4, March 18, and March 24), respectively.

Oversight of negotiations and agreements. President Trump wrote on social media on March 23 that the United States and Iran had had "VERY GOOD AND PRODUCTIVE CONVERSATIONS REGARDING A COMPLETE AND TOTAL RESOLUTION OF OUR HOSTILITIES"; Iran's foreign minister denied publicly that such talks had taken place.⁵⁸ Congress could act to support, negate, or otherwise counter any accord with Iran by lifting or imposing new sanctions, or take action with respect to Administration moves to do so. A U.S. agreement related to Iran's nuclear program would trigger congressional review requirements under the 2015 Iran Nuclear Agreement Review Act (INARA, P.L. 114-7).

Sanctions. Sanctions have been a component of congressional action toward Iran, including during the current conflict: on March 16, the House passed by unanimous consent H.R. 1422, which would expand sanctions authorities related to Iranian petroleum or petrochemical products. Congress could take action related to the Administration's main public action related to such sanctions during the conflict, the March 20, 2026 General License U, which authorizes otherwise sanctionable transactions related to the export of Iranian crude oil or petroleum products.⁵⁹ Alternatively, a new government in Iran (depending on its composition) could seek a rapid lifting of U.S. sanctions and extensions of U.S. support. Such developments may be considered alongside proposals to maintain influence over such a new government until its conduct and strategic orientation becomes more certain (as with the situation in Syria since 2025).

U.S. military assistance in Iran. Congress could consider whether or on what terms to authorize or prohibit support for other countries or entities inside Iran, including ethnic minority-oriented armed groups or other regime opponents. State collapse in Iran could raise debates similar to those that dominated congressional and executive branch action in other states weakened by civil conflict over the past 25 years (such as Iraq, Syria, Libya, Afghanistan, and Yemen), including the authorization of arms, training, and other support for various parties.

Footnotes

1.

White House, National Security Presidential Memorandum/NSPM-2, February 4, 2025.

2.

President Donald J. Trump, Truth Social post, February 5, 2026, https://truthsocial.com/@realDonaldTrump/posts/113950996936674770.

3.

Benoit Faucon, Michael R. Gordon, and Laurence Norman, "Iran seeks sanctions relief for nuclear limits in talks with U.S.," Wall Street Journal, April 12, 2025.

4.

For additional background and sourcing for this paragraph, see CRS In Focus IF13032, Israel-Iran Conflict, U.S. Strikes, and Ceasefire and CRS Insight IN12571, U.S. Strikes on Nuclear Sites in Iran.

5.

President Donald J. Trump, Truth Social post, June 17, 2025, https://truthsocial.com/@realDonaldTrump/posts/114699514822488706

6.

U.S. Department of Defense (DOD), Secretary of Defense Pete Hegseth and Chairman of the Joint Chiefs of Staff General Dan Caine Hold a Press Conference, June 22, 2025; "'This Week' Transcript 6-22-25: Vice President of the United States JD Vance, Sen. Tom Cotton & Rep. Jim Himes," ABC News, June 22, 2025. The department is "using a secondary Department of War designation," under Executive Order 14347 dated September 5, 2025.

7.

For more on the strikes' impacts on Iran's nuclear program, see CRS Insight IN12665, U.S. Military Operations Against Iran's Missile and Nuclear Programs.

8.

CRS In Focus IF13153, Protests in Iran: Possible U.S. Responses and Issues for Congress.

9.

President Donald J. Trump, Truth Social post, January 2, 2026, https://truthsocial.com/@realDonaldTrump/posts/115824439366264186; President Donald J. Trump, Truth Social post, January 13, 2026, https://truthsocial.com/@realDonaldTrump/posts/115888317758045915.

10.

U.S. Department of Defense (DOD), U.S. Central Command (CENTCOM), "Update from CENTCOM Commander on Operation Epic Fury," X post (video), March 11, 2026, https://x.com/CENTCOM/status/2031700131687379148.

11.

U.S. CENTCOM, X post, March 25, 2026, https://x.com/CENTCOM/status/2036908415956521033

12.

Christoph Koettl, "Iran's navy is weakened but U.S. still faces challenges in Strait of Hormuz," New York Times, March 6, 2026.

13.

Meghann Myers, "Iran's defense industrial base is 'functionally defeated': Hegseth," Defense One, March 13, 2026.

14.

Emanuel Fabian, "IDF carries out 'extensive' strikes on regime targets; Iran fires missiles at Israeli towns," Times of Israel, March 4, 2026; Neri Zilber and James Shotter, "Israel expects weeks-long war against Iran," Financial Times, March 4, 2026.

15.

Letter from Senator Chris Van Hollen et al. to Pete Hegseth, Secretary of Defense, March 11, 2026, https://www.vanhollen.senate.gov/imo/media/doc/letter_to_hegseth_on_minab_bombing_civcas_iran.pdf; Julian Barnes et al., "U.S. at fault in strike on school in Iran, preliminary inquiry says," New York Times, March 11, 2026.

16.

Human Rights Activists News Agency, "Day 25 of U.S. and Israeli attacks on Iran," March 24, 2026.

17.

Catie Edmondson, "Pentagon Tells Congress First Week of Iran War Cost More Than $11.3 Billion," New York Times, March 11, 2026.

18.

One think tank estimated the cost of the first 100 hours of the operation at $3.7 billion. Mark F. Cancian and Chris H. Park, $3.7 Billion: Estimated Cost of Epic Fury's First 100 Hours, Center for Strategic and International Studies, March 5, 2026. Another think tank estimated the cost between $11.2 billion and $14.5 billion, "including positioning maritime and aviation assets in the Middle East starting at the end of December." Elaine McCusker and Richard Sims, Epic Fury Is Worth the Cost, American Enterprise Institute, March 11, 2026.

19.

Sudiksha Kochi and Mike Lillis, "'Inevitable' Iran funding request sets up another big clash in the Capitol," The Hill, March 13, 2026.

20.

CRS In Focus IF12668, U.S. Army Small Uncrewed Aircraft Systems Programs.

21.

Nava Freiberg, "Report: Trump administration has asked Israel not to strike more Iranian oil facilities," Times of Israel, March 10, 2026.

22.

Donald J. Trump (@realDonaldTrump), "If Iran ... ," Truth Social, March 21, 2026, https://truthsocial.com/@realDonaldTrump/posts/116269822349947644.

23.

Donald J. Trump (@realDonaldTrump), "I am pleased ... ," Truth Social, March 23, 2026, https://truthsocial.com/@realDonaldTrump/posts/116278232362967212.

24.

AJ Jaff, "Iran's missile fire has collapsed by 92%. What comes next?" Jerusalem Post, March 10, 2026.

25.

Zia ur-Rehman et al. See, "Civilians killed by strikes in Gulf states are almost all migrant workers," New York Times, March 10, 2026.

26.

Helen Cooper and Eric Schmitt, "Iran's attacks force U.S. troops to work remotely," New York Times, March 25, 2026.

27.

CRS In Focus IF11548, Assisting and Evacuating U.S. Citizens Abroad During International Crises.

28.

CRS Report R45281, Iran Conflict and the Strait of Hormuz: Impacts on Oil, Gas, and Other Commodities.

29.

Josh Campbell, "US intelligence community ramps up warnings of possible retaliatory attacks by Iran," CNN, March 10, 2026; A.J. Vicens and Christy Santhosh, "Iran-linked hackers attack US medical device maker Stryker," Reuters, March 11, 2026.

30.

White House, "President Donald J. Trump on the United States military major combat operations in Iran," video, February 28, 2026.

31.

White House, "Operation Epic Fury: Decisive American power to crush Iran's terror regime," March 12, 2026.

32.

President Donald J. Trump (@realDonaldTrump), Truth Social, March 14, 2026, https://truthsocial.com/@realDonaldTrump/posts/116227904143399817.

33.

President Donald J. Trump (@realDonaldTrump), Truth Social, March 20, 2026, https://truthsocial.com/@realDonaldTrump/posts/116263563453969628.

34.

Spencer Kimball, "U.S. is allowing Iranian tankers through Strait of Hormuz, says Bessent," CNBC, March 16, 2026; "Hormuz 'open' to most, closed only to 'enemies': Iran allows limited oil transit amid war," TRT World, March 16, 2026.

35.

Israeli Prime Minister's Office, "Prime Minister's Office Announcement," February 8, 2026; Rina Bassist, "As US-Iran talks set to begin, Israel struggles to shape Trump's options," Al-Monitor, February 5, 2026.

36.

Anat Peled, "Netanyahu Urges Iranians to Rise Up," Wall Street Journal, February 28, 2026; Prime Minister of Israel (@IsraeliPM), X post, March 10, 2026 – 3:27 PM, https://x.com/IsraeliPM/status/2031452019861459240.

37.

Mark Mazzetti et al., "Israel Planned to Ignite Mass Uprising in Iran, But It Failed to Emerge," New York Times, March 23, 2026; Nava Freiberg, "Israeli ministers, security officials reportedly say Iranian regime collapse could take a year, amid 'fog' over war's length," Times of Israel, March 10, 2026.

38.

Asharq al-Awsat, "Israel Says Iran's New Supreme Leader a 'Tyrant' Who Will Continue 'Regime's Brutality,'" March 9, 2026.

39.

See, for example, Iranian Parliament Speaker (@mb_ghalibaf), X post, March 10, 2026, https://x.com/mb_ghalibaf/status/2031429904907042998.

40.

See, for example, Jon Gambrell, "Analysis: Iran war becomes a contest of who can take the most pain," Associated Press, March 11, 2026.

41.

Farnaz Fassihi, "Intrigue, power plays, and rivalries: Inside the rise of Mojtaba Khamenei," New York Times, March 16, 2026.

42.

Adam Chamseddine, "Lebanon's prime minister mulls sacking army chief over Hezbollah disagreements," Middle East Eye, March 11, 2026.

43.

See, for example, the Kata'ib Hezbollah statement reported on March 22; Tammuz Intel (@Tammuz_Intel), X post, March 22, 2026, https://x.com/Tammuz_Intel/status/2035868050218467399.

44.

"Russia and China pledge support to Iran's new Supreme Leader Mojtaba Khamenei amid ongoing war," TRT World, March 9, 2026.

45.

"Russia is helping Iran with intel to target and kill Americans, says top EU diplomat," CBS News, March 26, 2026; U.S. Department of the Treasury Office of Foreign Assets Control (OFAC), General License 133, March 5, 2026 General License 134, March 12, 2026.

46.

President Donald J. Trump (@realDonaldTrump), Truth Social post, March 9, 2026, 8:30 p.m., https://truthsocial.com/@realDonaldTrump/posts/116202054617775180; March 14, 2026, 10:04 a.m., https://truthsocial.com/@realDonaldTrump/posts/116227904143399817.

47.

United Nations, "Security Council Adopts Resolution 2817 (2026) Condemning Iran's 'Egregious Attacks' against Neighbours as Middle East Violence Rapidly Escalates," March 11, 2026, https://press.un.org/en/2026/sc16315.doc.htm.

48.

International Energy Agency, Oil Market Report – March 2026, March 12, 2026; Gavin Maguire, "Iran war deals harder blow to natural gas than oil," Reuters, March 24, 2026.

49.

"Even the best-case scenario for energy markets is disastrous," Economist, March 22, 2026.

50.

Kailyn Rhone, "It's not just oil. The Iran war is disrupting many essential goods," New York Times, March 10, 2026.

51.

Carnegie Endowment for International Peace, "The other global crisis stemming from the Strait of Hormuz's blockage," March 12, 2026.

52.

Dominika Tomaszewska-Mortimer, "Middle East war risks pushing 45 million more people into acute hunger," UN News, March 17.

53.

Sanam Vakil, "Why Iran could become the next Iraq," Financial Times, March 14, 2026; Shira Efron in "War in Iran: Q&A with RAND Experts," RAND Corporation, March 10, 2026.

54.

"Trump says Iran 'wants to make a deal' as costs rise," Bloomberg, March 25, 2026.

55.

Emily Clark, "Kharg Island could be Iran's weak spot as Washington reportedly considers ground invasion options," ABC News, March 11, 2026; Michael Gordon and Laurence Norman, "If seizing Iran's nuclear material is the endgame, here's what it would take," Wall Street Journal, March 15, 2026.

56.

Lara Seligman, "Pentagon is moving additional marines, warships to the Middle East," Wall Street Journal, March 13, 2026; Eric Schmitt, "Around 2,000 U.S. Paratroopers to be sent to the Middle East," New York Times, March 24, 2026.

57.

CRS In Focus IF13172, Iranian Kurds and Possible Support.

58.

President Donald J. Trump, Truth Social post, March 23, 2026, https://truthsocial.com/@realDonaldTrump/posts/116278159912794855.

59.

General license available at https://ofac.treasury.gov/recent-actions/20260320_33.