U.S.-Iran Tensions Escalate
Updated June 13, 2019
U.S.-Iran Tensions Escalate
Overview
Iranian Reaction
U.S.-Iran tensions have escalated as the Trump
Iran’s leaders have expressed intent to avoid conflict with
Administration took several significant steps in its
the United States while indicating that Iran will respond if
campaign of applying “maximum pressure” on Iran, and
attacked. Some Iranian statements have appeared
Iran responded. U.S. officials state that Iran-linked threats
provocative, including threats by the IRGC Navy
to U.S. forces and interests prompted the Administration to
Commander to close the Strait of Hormuz.
send additional military assets to the region. Yet, President
On May 19, a rocket was fired into the fortified “Green
Donald Trump, while warning Iran not to take action
Zone” in Baghdad but caused no injuries or damage. Iran-
against the United States, has said he prefers a diplomatic
backed militias were widely suspected of the firing, but no
solution that would lower tensions. Members of Congress
U.S. or Iraqi determination of responsibility has been
have received additional information from the
announced. The incident came four days after the State
Administration about the causes of the uptick in U.S.-Iran
Department ordered “nonemergency U.S. government
tensions and Administration planning for further U.S.
employees” to leave U.S. diplomatic facilities in Iraq based
responses. Some in Congress have sought to minimize the
on assertions that there is a heightened threat of Iranian
potential for the tensions to escalate into conflict.
allies acting against the United States there.
Recent Administration Steps to Pressure Iran
In the Gulf region, on May 12-13, the United Arab Emirates
The developments that contributed to the tensions include
and Saudi Arabia asserted that four oil tankers and the
the following:
Saudi oil pipeline infrastructure had been attacked. Iran
denied involvement in the incidents, but on May 24, a
On April 8, 2019, the Administration designated the
Defense Department official attributed the tanker attacks to
Islamic Revolutionary Guard Corps (IRGC) as a Foreign
Terrorist Organization (FTO). Iran’s parliament
the IRGC. Some experts assert that the incidents in the Gulf
and in Iraq were orchestrated by Iran to send a message that
responded by enacting legislation declaring U.S. Central
it can cause instability if provoked. On June 13, 2019, two
Command (CENTCOM) and related forces in the
tankers in the Gulf of Oman were attacked. Secretary of
Middle East to be terrorists.
State Pompeo stated: “It is the assessment of the U.S.
government that Iran is responsible for today's attacks in the
As of May 2, 2019, the Administration ended a U.S.
Gulf of Oman. These attacks are a threat to international
sanctions exception for the purchase of Iranian oil to try
peace and security, a blatant assault on the freedom of
to drive Iran’s oil exports to “zero.”
navigation, and an unacceptable escalation of tension by
Iran.” The United States referred the matter to the United
On May 3, 2019, the Administration ended waivers
Nations Security Council.
under the Iran Freedom and Counter-Proliferation Act
(IFCA, P.L. 112-239) that allow countries to help Iran
The tensions affected Iran’s stance with respect to the
remain within stockpile limits set by the 2015 nuclear
agreement (Joint Comprehensive Plan of Action,
JCPOA. On May 8, President Hassan Rouhani announced
JCPOA).
that Iran would no longer abide by JCPOA restrictions on
stockpiles of low-enriched uranium and heavy water. He
On May 5, 2019, citing reports that Iran might be
also announced that unless the European Union (EU)
preparing its allies to attack U.S. personnel or
countries that have sought to preserve the JCPOA “fulfill
their commitments” to provide economic benefits of the
installations, National Security Adviser John Bolton
announced that the United States was accelerating the
JCPOA within 60 days, Iran would resume additional
previously planned deployment of the USS Abraham
aspects of uranium enrichment, including possibly
Lincoln Carrier Strike Group to the region and sending a
enriching to a higher level of purity. On May 22, 2019,
Iran’s Supreme Leader, Grand Ayatollah Khamene’i, said
bomber task force to the Persian Gulf region.
he had expressed to both leaders during JCPOA
negotiations that he “did not really believe” in the way they
On May 8, the President issued Executive Order 13871,
blocking the U.S.-based property of persons and entities
handled the agreement. The statement suggests that Iran
determined by the Administration to have conducted
might pull out of the JCPOA entirely and that relatively
significant transactions with Iran’s iron, steel,
moderate leaders are in eclipse. Yet, a late May 2019 report
aluminum, or copper sectors.
by the International Atomic Energy Agency (IAEA)
indicated that Iran was still in compliance with its JCPOA
nuclear commitments.
https://crsreports.congress.gov
U.S.-Iran Tensions Escalate
European Responses
a few thousand to several tens of thousands of U.S. military
The EU has sought to de-escalate tensions and urged Iran
personnel—to deter Iran from any attacks. On May 24, the
not to leave the accord entirely. A May 9 joint statement by
Defense Department said that the President has approved a
the EU and the foreign ministers of France, the United
plan to augment U.S. defense and deterrence against Iran by
Kingdom, and Germany stated that “We reject any
deploying to the Gulf region an additional 900 military
ultimatums” by Iran but, “At the same time we recall our
personnel, extending the deployment of another 600 that
own firm commitments under the agreement including as
were sent earlier to operate Patriot missile defense
regards sanctions lifting…” Secretary of State Pompeo
equipment, and sending additional combat and
attended meetings with EU officials on May 13 to brief
reconnaissance aircraft. Should hostilities erupt, the United
them on U.S. intelligence about the heightened Iranian
States has the capability to implement a range of options
threat, but, at the conclusion of the meetings, UK Foreign
such as air strikes on Iranian targets.
Secretary Jeremy Hunt stated, “We [EU] are very worried
about the risk of a conflict happening by accident, with an
Status Quo. The tensions could remain, but neither escalate
escalation unintended really on either side.”
nor de-escalate, particularly if the U.S.-Iran discourse
remains mostly bellicose but without any further incidents.
De-Escalation. Iran could potentially try to de-escalate,
[The U.S. military deployments] send a clear
perhaps by taking up U.S. offers to negotiate a broader,
and unmistakable message to the Iranian
revised JCPOA, though U.S. demands for a new JCPOA are
regime that any attack on United States
extensive and many see that as unlikely. A May 16
interests or on those of our allies will be met
Washington Post report indicated that President Trump
with unrelenting force. Statement by National
wants to de-escalate tensions, avoid conflict with Iran, and
Security Adviser John Bolton, May 5.
negotiate a revised JCPOA. Secretary Pompeo has
reportedly sought to establish new channels of contact with
What they [Iranian leaders] should be doing is
Iran via Sultan Qaboos of Oman, with whom Pompeo
calling me up, sitting down; we can make a
talked on May 16, 2019. Japan’s Prime Minister Shizo Abe
deal, a fair deal. ... We're not looking to hurt
sought to mediate a de-escalation during his visit to Iran on
Iran…But they should call, and if they do, we're
June 12-13, 2019, the first visit to Iran by a Japanese leader
open to talk to them. President Donald Trump,
since the Islamic revolution. That visit followed one by
May 9.
Germany’s foreign minister to Tehran in early June. Iranian
leaders have said they would not engage in talks with the
If Iran wants to fight, that will be the official
United States unless the United States resumes
end of Iran. Never threaten the United States
implementing the JCPOA. If Iran was responsible for the
again! President Donald Trump, May 20, 2019.
June 13 tanker attacks, this could suggest Iran does not
intend to de-escalate.
Scenarios and Possible Outcomes
Potential Implications for Congress of Escalation
There are several directions the escalating tensions might
With the chances of intended or unintended U.S.-Iran
take, any of which might involve congressional oversight,
conflict seemingly heightened, the question of authorization
potential considerations of new sanctions, authorization or
for the use of military force against Iran arises. No
limitations on the use of military force, or congressional
legislation has been enacted authorizing the use of force
steps to support regional partners potentially affected by
against Iran, although successive Presidents have asserted
conflict. The IRGC’s Qods Force (IRGC-QF) arms, trains,
legal and constitutional authority to initiate any military
and advises allies and proxies throughout the Middle East
operation. Several efforts in the Senate to block the use of
region, including in Syria, Lebanon, Iraq, Yemen, and
funds for offensive U.S. military action against Iran have
Bahrain. Accordingly, Iran and/or its allies have numerous
not advanced. The Prevention of Unconstitutional War with
ways to take aggressive action or counter U.S. actions. The
Iran Act of 2019 (H.R. 2354/S. 1039) would prevent the use
of funds for “kinetic military operations in or against Iran”
published State Department report on international
terrorism has consistently asserted that Iran and its key ally,
except in case of an imminent threat.
Lebanese Hezbollah, have a vast network of agents in
Europe, Latin America, and elsewhere that could act against
Should the Administration assert authority to use force
U.S. personnel and interests far outside the Middle East.
against Iran, another issue might be the justification for
using existing authorizations. At a Senate Foreign Relations
Escalation. U.S. and Iranian officials have said they do not
Committee hearing on April 10, 2019, Secretary of State
want armed conflict. However, leaders on both sides have
Pompeo, when asked if the Administration considers the
said they will respond with force if the other attacks,
use of force against Iran as authorized, answered that he
increasing the potential for miscalculation to produce
would defer to Administration legal experts on that
conflict. There are over 60,000 U.S. forces deployed to the
question. However, he suggested that the 2001
region, including those stationed at military facilities in the
authorization for force against those responsible for the
Arab states of the Gulf Cooperation Council (GCC: Saudi
September 11 terrorist attacks could potentially apply to
Arabia, Kuwait, UAE, Qatar, Oman, and Bahrain). Press
Iran, asserting that “[Iran has] hosted Al Qaida. They have
reports indicated that the Administration was considering a
permitted Al Qaida to transit their country. There-there’s no
number of options to add forces—with reports ranging from
https://crsreports.congress.gov
U.S.-Iran Tensions Escalate
doubt there is a connection between the Islamic Republic of
Kenneth Katzman, Specialist in Middle Eastern Affairs
Iran and Al Qaida. Period. Full stop.”
IF11212
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11212 · VERSION 19 · UPDATED