CRS INSIGHT Prepared for Members and Committees of Congress
Since the October 7, 2023, attacks led by Hamas (a U.S.-designated foreign terrorist organization, or FTO), conflicts between Israel and Iran and/or its allies have spread across the Middle East. After Israel and Iran exchanged direct fire in April 2024, three incidents in July led to another potential inflection point:
• Civilians killed in Golan Heights. On July 27, a rocket fired from Lebanon reportedly killed 12 young people in the Druze town of Majdal Shams in the Golan Heights. U.S. and Israeli officials said Lebanese Hezbollah (another FTO) was responsible despite the group’s denial.
• Hezbollah military leader killed in Lebanon. On July 30, Israeli authorities said that an Israeli drone strike in Beirut killed Hezbollah senior commander Fuad Shukr, whom Israel blamed for the Golan Heights attack (and was reportedly involved in the 1983 bombing of the U.S. Marine Corps Barracks in Beirut).
• Top Hamas leader killed in Iran. On July 31, Ismail Haniyeh—the top political leader of Hamas—was reportedly assassinated by a remotely detonated bomb while visiting Tehran for the inauguration of Iranian President Masoud Pezeshkian. Hamas and Iran blamed Israel for the killing; Israel has not commented.
In blaming Israel for Haniyeh’s death, Iranian Supreme Leader Ayatollah Ali Khamenei reportedly ordered direct retaliation against Israel, and Hezbollah leader Hassan Nasrallah publicly pledged to carry out a reprisal attack on Israeli targets for Shukr’s killing. In April 2024, Iranian leaders declared a “new equation,” stating that Iran would meet any Israeli attack against Iranian “interests, assets, figures, and citizens anywhere” with a counterattack. In the weeks following the July incidents, some analysts assessed that Iran’s initial “shock and humiliation” in response to Haniyeh’s killing had “given way to a more realistic assessment of the risk and reward of war with Israel.” The Biden Administration has moved additional U.S. military forces to the region and has pledged to aid Israel in its defense.
Factors potentially influencing key actors’ conflict-related decisions include the following:
• Israel. What risks Israel might accept in an effort to counter and deter Iran and its allies, and to return some 60,000 evacuees to northern Israel. Such risks may affect Israel’s
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ongoing war with Hamas and prospects for a cease-fire, as well as its overall military and self-defense capacity.
• Iran. How Iran perceives that its responses may strengthen or weaken its capacity to deter future Israeli military operations against it or its partners.
• Hamas. What the implications are of Haniyeh’s reported killing, and his replacement by Gaza-based Yahya Sinwar, for Hamas’s approach to cease-fire and hostage negotiations with Israel.
• Hezbollah. Whether Hezbollah’s perceives that its military options and capabilities would strengthen its deterrence of Israel or magnify the threat of escalation, when considered alongside the group’s relations with Iran and its own future as a militia and political party in troubled Lebanon.
On August 25, Israel and Hezbollah engaged in a major exchange of fire. Israel stated that it acted on intelligence of an impending attack to preemptively strike Hezbollah launchers in Lebanon with more than 100 aircraft, and Hezbollah sent hundreds of rockets and drones into northern Israel. While Hezbollah claimed that its retaliatory operation was successful in targeting Israeli military bases— including the Glilot base near Tel Aviv that reportedly houses key Israeli intelligence units—Israel asserted that it had largely thwarted Hezbollah’s efforts and that none of its bases incurred damage. Reports suggest that at least three people died in Lebanon, and one Israeli sailor was killed from shrapnel from an Israeli interceptor missile.
In the immediate aftermath of this exchange, Israel and Hezbollah reportedly swapped messages that neither wants to escalate further. Nasrallah stated that Hezbollah reserves the right to respond later if it decides the results of its attack are not sufficient. Israeli Prime Minister Benjamin Netanyahu said that Israel’s actions were a step aimed at changing the situation in the north, returning Israeli evacuees to their homes, and were not “the end of the story.”
Israeli officials reportedly gave U.S. counterparts advance notice of Israel’s preemptive strike, with the Biden Administration supposedly approving Israel’s actions against Hezbollah while warning Israel to avoid actions that could lead toward full-scale war. Following the Israel-Hezbollah exchange, Secretary of Defense Lloyd Austin “reiterated Israel's right to defend itself and the United States’ ironclad resolve to support Israel’s defense,” and ordered the two U.S. carrier strike groups in the region to remain there. Earlier in August, Secretary Austin also had dispatched a guided-missile nuclear submarine to the region.
In the wake of the August 25 exchange, whether and how Iran or Hezbollah might engage in further reprisals against Israel remains unclear. Iran’s foreign minister said that Iran’s reaction to Haniyeh’s killing “is definitive, and will be measured & well calculated.” Hezbollah has pledged to halt cross-border attacks in the event of a Gaza cease-fire, though it is uncertain whether this would apply to potential additional retaliation for Shukr’s death.
In assessing potential legislative and oversight options, Congress may consider the following.
Escalation could have political-military implications for Israel and other U.S. partners in the Middle East, and affect bilateral and multilateral U.S. coordination efforts regarding regional security. Israel may face
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challenges in maintaining military strength vis-à-vis Gaza, Lebanon, and the West Bank, while also facing threats or potential threats from Iran and Iran-backed actors in Yemen, Syria, and Iraq. Hezbollah’s battle- tested militia, proximity to Israel, and large arsenal of drones, rockets, and missiles appears to pose a considerably greater sustained threat to Israel than Hamas does.
Congress and the Biden Administration may consider the nature of Israeli operations and any potential shortfalls in Israel’s defense capacity and stockpiles when weighing future direct U.S. involvement in Israel’s defense; the movement and use of military assets and personnel to and within the region; and/or the timing, nature, and volume of arms shipments.
Heightened regional conflict may put at further risk thousands of U.S. military personnel deployed to and near the eastern Mediterranean and Persian Gulf, along with U.S. citizens residing in the region.
Jim Zanotti Specialist in Middle Eastern Affairs
Clayton Thomas
Specialist in Middle Eastern Affairs
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