Following Hamas’ attack on October 7th, the U.S. government acted swiftly to dissuade other regional actors such as Hizballah or Iran from intervening in the latest round of Israeli-Hamas hostilities. In his remarks on the attacks, President Joseph Biden was blunt: “Let me say again — to any country, any organization, anyone thinking of taking advantage of this situation, I have one word: Don’t. Don’t.” Backing up the president’s words, the Pentagon approved a deployment extension for the USS Gerald Ford carrier strike group in the eastern Mediterranean and redirected a second, the USS Dwight D. Eisenhower carrier strike group, to the Middle East.
Whether as a result of U.S. efforts at deterrence or other strategic considerations, the region has thus far averted an all-out escalatory spiral. But the United States has not been able to avoid direct military involvement altogether as evidenced by repeated strikes and counterstrikes with Iran-backed groups in multiple theaters of the Middle East.
The involvement of U.S. forces in yet more conflicts in the Middle East raises both significant policy and legal issues. Most pressingly, the United States is faced with the question of how to mitigate risks to U.S. forces and prevent further regional escalation. But the simmering regional hostilities over the last few months also highlight the inadequacies, at least in practice, of the U.S. domestic law framework designed to regulate when the United States goes to war. The involvement of U.S. armed forces in hostilities in this tinderbox—without congressional authorization—should spur the legislative branch into action, including to enact long overdue reforms.
Hostilities in Two Theaters
U.S. forces are engaged in hostilities in both the Iraq and Syria theater and in the Red Sea, in conflicts with varying degrees of connection to the fighting in Gaza.
In Iraq and Syria, Iran-backed groups renewed drone and rocket launches against U.S. forces on October 17th. Although periodic hostilities between the U.S. and Iran-backed forces had occurred for years, until October there had been a months-long lull in attacks on U.S. troops in both countries. In October, however, groups belonging to an umbrella entity calling itself the “Islamic Resistance”(which includes Kata’ib Hizbollah, Harakat al-Nujaba, and Kata’ib Sayed al-Shuhada) not only resumed targeting U.S. troops, they intensified their attacks, seemingly in retribution for Israeli actions in Gaza. From October 17th to the end of December, these groups have attacked U.S. forces over 100 times. Although the attacks on U.S. forces subsided somewhat during the short-lived pause in fighting in Gaza in late November, they picked up once again as the fighting in Gaza recommenced. The U.S. has responded with strikes against these groups and facilities connected with their operations, including with at least six rounds of airstrikes ordered by President Biden as well as additional strikes apparently ordered by lower-level commanders. Some of these U.S. strikes have killed members of the Islamic Resistance. The Pentagon unconvincingly maintains that “Gaza has not spread out into a wider regional conflict” and that the attacks on U.S. forces in Iraq and Syria are unrelated to the war in Israel-Palestine.
Iraq-Syria is not the only theater in the region where U.S. forces are currently exchanging fire as a result of the Gaza conflict. The Houthis in Yemen have responded to the fighting in Israel-Palestine by launching attacks at Israel, commercial vessels with alleged connections to Israel in the Red Sea, and even U.S. warships themselves. As a result, for two months, the U.S. Navy has also engaged in fighting in the waters and airspace off the coast of Yemen.
These U.S. actions, beginning on October 19, have primarily involved a number of U.S. warships repeatedly shooting down in international airspace over the Red Seas drones and missiles launched from Yemen. Several of these actions were taken in apparent “unit self-defense” of U.S. forces, even though the targets of the projectiles have not always been clear. On November 8th, possibly in response to these actions by the U.S. Navy, the Houthis shot down a U.S. Reaper drone over the Red Sea. In addition, on November 26th, after the USS Mason intervened in the attempted seizure of a merchant vessel by apparent pirates, ballistic missiles were fired from Houthi-controlled Yemen towards the vessel, according to U.S. Central Command. On the occasion of the Army-Navy football game, the crew of the U.S. Navy released a video boasting that the USS Carney was “22-0,” an apparent reference to the number of Houthi projectiles it had shot down.
But attacks persist. On December 16th, the USS Carney shot down 14 “one-way attack drones.” On the 18th, the Carney responded to an attack on the M/V Swan Atlantic with multiple projectiles. By mid-December, the continued Houthi attacks on commercial vessels had caused some major shipping companies to halt voyages through the Red Sea along with shipments of petroleum by BP.
The establishment of the U.S.-led, multinational Operation Prosperity Guardian to deter and respond to Houthi attacks and ensure freedom of navigation in the Red Sea did not bring hostilities to an end. The Houthis continued to launch anti-ship ballistic missiles into international shipping lanes of the Red Sea, and on December 23rd, the USS Laboon shot down four drones described as “inbound.” The fighting has also involved air-to-air combat, with F/A-18s shooting down Houthi projectiles. After the Maersk Hangzhou container ship was reportedly struck by a missile, the USS Gravely responded to assist the vessel and, in the process, shot down two further anti-ship ballistic missiles fired toward the ships, according to U.S. Central Command. A fatal clash closed out the year, when the Hangzhou again came under attack, this time by Houthi small boats and U.S. Navy helicopters responded to its distress call. The Houthi boats reportedly fired upon the helicopters, which returned fire, sinking three of the four boats, and killing the crews. According to the Pentagon, between November 19th, 2023 and January 4th, 2024, the Houthis had launched 25 attacks on merchant vessels transiting the southern Red Sea and the Gulf of Aden, with a combination of drones, fast boats, land attack cruise missiles, and for the first time anywhere, anti-ship ballistic missiles.
Despite these regular military actions, the Pentagon implausibly claims that “[w]e’re not in an armed conflict with the Houthis.”
Legal Background: The 1973 War Powers Resolution
The statutory framework intended to govern the unilateral use of force by the president, such as the ongoing fighting in Iraq-Syria and the Red Sea, is the War Powers Resolution. Congress enacted this law over President Nixon’s veto in 1973 to reassert its constitutional prerogatives with respect to war and peace in the final stages of the Vietnam War. Specifically, Congress sought to forestall any president from taking the country to war without congressional authorization or even without congressional awareness (as had allegedly been the case for aspects of the war in Indochina, such as the incursion into Cambodia).
To this end, Section 4(a) of the Resolution establishes reporting requirements to prevent the president from taking the country to war in secret. In the absence of a declaration of war or other statutory authorization, the president is subject to multi-tiered obligations to report on certain triggering activities of U.S. armed forces within 48 hours to Congress. First, under subsection 4(a)(1) she must report when U.S. military forces are introduced into “hostilities” or introduced into “situations where imminent involvement in hostilities is clearly indicated by the circumstances.” Such hostilities reports are the focus of this essay. Second, even if U.S. forces are not engaging in hostilities, subsection 4(a)(2) requires the president to report the introduction of “combat equipped” forces into a country (the executive branch defines “combat-equipped” as forces equipped with crew-served weapons such as machine guns requiring more than one person to operate and mortars). Third, pursuant to subsection 4(a)(3), the president must also report a substantial enlargement of such combat equipped forces in a country where such forces are already present.
Notably, under Section 5(b) of the 1973 Resolution, the submission of a report under the first of these scenarios — introduction of U.S. forces into hostilities or situations of imminent hostilities — also starts a 60-day clock for the withdrawal of U.S. armed forces from such hostilities unless Congress declares war or otherwise enacts specific statutory authorization for the use of force. Further, the War Powers Resolution provided a mechanism in section 5(c) for Congress to order the removal of U.S. forces from hostilities through a concurrent resolution—that is, a resolution passed by both houses of Congress but not presented to the president for his or her signature or veto. (Particularly following the Supreme Court’s 1983 decision in INS v. Chadha that ruled unconstitutional the legislative veto, section 5(c) is widely viewed as unconstitutional. In the wake of Chadha Congress enacted expedited procedures for joint resolutions requiring the removal of U.S. armed forces from hostilities, which does require presentment to the president.)
Although Congress did not define “hostilities,” or “imminent involvement in hostilities,” in the text of the statute, the legislative history indicates that Congress intended those terms to be construed broadly in order to establish a low threshold for both the reporting and withdrawal provisions of the War Powers Resolution. The House Foreign Affairs Committee’s report on the Resolution explains:
The word hostilities was substituted for the phrase armed conflict during the subcommittee drafting process because it was considered to be somewhat broader in scope. In addition to a situation in which fighting actually has begun, hostilities also encompasses a state of confrontation in which no shots have been fired but where there is a clear and present danger of armed conflict. “Imminent hostilities” denotes a situation in which there is a clear potential either for such a state of confrontation or for actual armed conflict.
Unsurprisingly, the executive branch has espoused different, narrower interpretations of these terms that are less likely to constrain the president’s ability to use military force without congressional authorization. In the most oft-repeated formulation, the State Department’s Legal Adviser informed Congress in a 1975 letter that its working definition of “hostilities” meant “a situation in which units of the U.S. armed forces are actively engaged in exchanges of fire with opposing units of hostile forces.” “Imminent hostilities” means “a situation in which there is a serious risk from hostile fire to the safety of United States forces.” As a matter of statutory interpretation, it is questionable how much weight the post-enactment views of the executive branch should be accorded as opposed to the pre-enactment interpretation of the legislature that passed the statute into law over the president’s veto.
War Powers Reporting Since October 7th
The White House has filed six War Powers reports since October 27th in connection with U.S. retaliatory strikes directed by President Biden. For the purposes of the War Powers Resolution—and the constitutional separation of powers—it is perhaps more notable what the White House has not reported under the Resolution. The War Powers reports have only been submitted in connection with pre-planned strikes specifically authorized by the president in Iraq and Syria. These include, it seems most recently, a January 4th strike authorized by President Biden targeting the leader of one of the Islamic Resistance groups in Baghdad (see below).
However, reports have not been submitted for other U.S. military actions in Iraq and Syria, such as one by a drone in Iraq on December 3rd, which seem to have been taken in immediate “unit self-defense” and authorized by a lower-level commander. Nor has the administration submitted reports for the over 100 attacks on U.S. forces by Iran-backed armed groups in Iraq and Syria since October 17th. The administration has also failed to submit War Powers reports in connection with U.S. naval actions in the Red Sea, despite the repeated U.S. engagements there, including the firing of ballistic missiles from Yemen, the downing of the U.S. Reaper, aerial shootdowns, and the fatal firefight on New Year’s Eve.
Avoiding the 60-Day Clock
Taken together, the Biden administration’s reporting practice suggests that it is consciously seeking to avoid running out the Resolution’s 60-day clock for removing U.S. forces. Although the executive branch has not publicly explained its legal thinking, it may be relying on a few different theories.
First, the submission of multiple reports in connection with regular ongoing hostilities, such as those in Iraq and Syria, is consistent with a “salami slicing” theory under which a single conflict is subdivided into multiple “one-off” events in order to argue that the 60-day clock has stopped and restarted. The executive branch has previously treated ongoing armed conflicts as a series of discrete events rather than continuous hostilities both during the 1987-88 Tanker War in the Persian Gulf and during the early phase of the U.S.-led campaign against the Islamic State in 2014.
Narrow Interpretations of “Hostilities”
Second, the administration seems to construe “hostilities” narrowly – perhaps even more so than prior executive branch interpretations of the phrase. The administration appears to distinguish between pre-planned deliberate strikes ordered by the President, which merit a War Powers report, from on-the-spot reactions (including those taken in unit self-defense), in terms of what constitutes the introduction of U.S. forces into hostilities. The White House also seems to regard attacks on U.S. forces but not by U.S. forces as not constituting hostilities.
There is certainly some, though inconsistent, executive branch precedent for espousing or relying on constrained readings of “hostilities” beyond the touchstone 1975 “exchanges of fire” interpretation.
In a 1980 opinion, OLC took the position that
if our armed forces otherwise lawfully stationed in a foreign country were fired upon and defended themselves, we doubt that such engagement in hostilities would be covered by the consultation and reporting provisions of the War Powers Resolution. The structure and thrust of those provisions is the “introduction” of our armed forces into such a situation and not the fact that those forces may be engaged in hostilities. It seems fair to read “introduction” to require an active decision to place forces in a hostile situation rather than their simply acting in self-defense.
Similarly, when in 1987 during the Tanker War a U.S. F-14 fighter fired two missiles at an unidentified target it deemed a threat over the Persian Gulf, even though the missiles missed, Congress asked why the event did not constitute “involvement in imminent hostilities” and thus trigger the War Powers Resolution. In a letter to the Chairman of the House Foreign Relations Committee, the State Department took the position that “[i]solated incidents involving defensive reactions by U.S. forces do not necessarily indicate that imminent involvement in hostilities is clearly indicated by the circumstances… In this particular case, it is not clear that an attack on U.S. forces was imminent, and in fact no such attack occurred.”
There is also recent practice in which the executive branch has declined without explanation to report incidents under the War Powers Resolution in which U.S. drones were shot down or where U.S. forces employed missile defense systems. The Trump administration did not report the shoot down of a Reaper in 2019 by the Houthis, nor the 2019 Iranian downing of a U.S. drone over the Persian Gulf, which nearly resulted in a retaliatory U.S. attack. Moreover, the Biden administration did not report when in 2022, U.S. forces stationed in the United Arab Emirates employed a Patriot missile defense system to shoot down a Houthi missile, the first combat usage of the Patriot by the United States since the 2003 U.S. invasion of Iraq. Neither the Trump nor Biden administrations publicly explained their legal theories for not reporting these incidents under the Resolution, though their rationales may well have rested on straitened readings of “hostilities.”
Yet, if the White House is relying on an interpretation of “hostilities” under the War Powers Resolution that distinguishes between pre-planned operations vs. on-the-spot reactions in “unit self-defense,” with the latter type of action somehow below the threshold for reporting under the law, it is not a distinction the executive branch has consistently maintained. In contrast to the recent reports from the Biden administration that indicate clear presidential involvement in the military actions (“I directed…”), both the facts and framing of some prior War Powers notifications indicate they pertained to on-the-spot responses ordered at lower levels than the President. For example, in August 1983, U.S. Marines deployed to Lebanon engaged in combat after coming under attack. The Reagan administration reported the fighting “consistent with” the War Powers Resolution, even though in returning fire the marines were (unsurprisingly) acting “[a]s contemplated by their rules of engagement” rather than at the specific direction of the Commander-in-Chief of the United States Armed Forces.
In addition, in reporting on the March 1986 Gulf of Sidra incident involving air and naval fighting with Libya, the Reagan administration explicitly acknowledged that at least some of the actions were ordered by “the U.S. Commander” and not the President himself. Similarly, in an incident with clear parallels to the New Year’s Eve clash in the Red Sea, in July 1988 during the Tanker War, U.S. helicopters in the Persian Gulf responded to the distress call of a tanker under attack by (presumably Iranian) small boats, were fired on by the boats and returned fire in self-defense.
The failure of the Biden administration to report the fatal December 31st firefight in the Red Sea is thus hard to square with at least some prior executive branch practice. Based on the reported facts, the New Year’s Eve incident fits squarely within the executive branch’s own touchstone definition of “exchanges of fire with opposing units of hostile forces” from 1975 and closely resembles the July 1988 clash reported by the Reagan White House.
Even if the executive branch is currently operating under an unduly narrow definition of “hostilities”, Congress has not necessarily accepted nor endorsed such an interpretation. For example, in the context of the Reagan administration’s ill-fated deployment of U.S. forces to Lebanon in 1983 without prior congressional authorization and Congress’s consideration of a time-limited use of force authorization, the Senate Foreign Relations Committee pushed back against cramped readings that would exclude on-the-spot defensive actions. In a report, the committee stated:
Arguments have been made, that a hostile situation was not indicated by the present circumstances because the Marines:
(a) Only returned rather than initiated fire;
(b) Acted only in self-defense;
(c) Remained essentially in one location. rather than taking offensive actions;
(d) Performed a mission of “peacekeeping,” “presence,” or “Interposition”.
However, there is nothing in the legislative history of the War Powers Act to indicate that any of these considerations would alter the fact that “hostilities” are indicated.
(Notably, then Senator Biden who opposed the draft resolution in committee, included a separate dissent in the report to emphasize that “I would not support any authorization for troops in Lebanon of any duration absent much more clearly defined goals and a reasonable prospect of attaining those goals.”)
Finding the Statute
In its recent reports, the administration also hinted at an alternative mechanism for escaping the limitations of the 60-day clock. In its November 22nd and December 27th letters to Congress, the White House stated that President Biden ordered the military actions “pursuant to [his] constitutional authority” but also that he “directed the strikes in order to protect and defend our personnel who are in Iraq [and Syria] conducting military operations pursuant to the 2001 Authorization for Use of Military Force.” Thus, although the legal basis for the strikes themselves rested on the president’s constitutional authority under Article II, the U.S. forces in Iraq and Syria had an additional, statutory legal basis for their underlying operations in those countries. By invoking a statutory basis for the U.S. presence in Iraq and Syria, the White House no doubt hoped to head off any claims that the time-limit for Article II-based use of force has expired.
The Biden administration took a further step regarding statutory authority its most recent, January 5th War Powers notification. In an unprecedented move, this report to Congress neither identified what military action was being reported nor where the action had occurred. Instead, this information was seemingly hidden in a rare classified annex. But the hidden information could be inferred from the context and content of the report. The previous day, the Pentagon had publicly acknowledged a U.S. strike on Mushtaq Jawad Kazim al-Jawari, a leader of Harakat-al-Nujaba, in Baghdad. Further, for the first time in the Biden administration, the White House cited the 2002 Iraq AUMF in connection with a strike on an Iran-backed group. Specifically, the report states that President Biden directed the unidentified military action pursuant to his constitutional authority “and in accordance with the 2001Authorization for Use of Military Force  and the Authorization for Use of Military Force Against Iraq.”
Such a “finding the statute” approach would hardly be novel. In fact, the executive branch’s original invocation of the 2001 Authorization for the Use of Military Force (2001 AUMF) as a legal basis to fight the Islamic State came as the WPR’s clock was rapidly ticking to 60-days in 2014. The Obama administration commenced airstrikes against ISIS in Iraq on August 8, 2014. In late September, shortly before the 60-day mark, the administration announced that the 2001 AUMF (supplemented by the 2002 Iraq AUMF) provided statutory authority for U.S. hostilities against ISIS in Iraq and Syria. As a result, because the White House had prior congressional authorization to use military force (or so it argued) the deadline for withdrawing U.S. forces from hostilities did not apply.
By citing the 2001 AUMF in its November 22nd and December 27th letters to Congress, the Biden administration began preparing a similar theory. Just at the Obama administration did in 2014 for the counter-ISIS campaign, by invoking both the 2001 and 2002 AUMFs as authority for the unspecified military action reported on January 5th, the Biden administration seeks to circumvent the 60-day clock for strikes on Iran-backed groups in Iraq and Syria by shifting to reliance on statutory authority rather than solely Article II. (It also represented a departure from past Biden administration practice which was to rely exclusively on Article II for strikes on Iran-backed groups. The White House may have returned to theories of the Trump administration, which cited the decades-old war authorizations to fight al Qa’ida and topple Saddam Hussein as legal bases to strike Iran-backed groups and even Iranian general Qassem Soleimani. Amongst other arguments, the Trump administration contended that these statutes underpinning the counter-ISIS campaign provided ancillary authority to defend against other threats.) Although 60 days has elapsed from the date of the first of the renewed U.S. airstrikes on October 27th, the White House would likely contend (however implausibly) that it retains statutory authority under both the 2001 and 2002 war authorization not only to keep U.S. forces in Iraq and Syria to “ensure the enduring defeat of ISIS” but also to continue striking Iran-backed groups in both countries.
The Need for Policy Off Ramps and Legal Guardrails
Despite the U.S. deployments of significant additional military assets to the Middle East since October 7th and repeated uses of force in both Iraq-Syria and the Red Sea, the Biden administration’s efforts at deterrence have not fully prevented the expansion of the Gaza conflict beyond Israel-Palestine. Nonetheless, the administration has been mindful of the dangers of escalation in these other theaters and has shown considerable forbearance in its use of military force in response to attacks both by Iran-backed groups in Iraq and Syria and the numerous launches and other provocations by the Houthis. And the administration has opposed the suggestion from some in Congress to enact a new war authorization against Iran-backed groups, including due to the escalatory signal it would send. The administration also continues to wisely resist calls from hawks in Congress to attack Iran directly. The fact is, the United States has few good military options for responding, as strikes against the Islamic Resistance in Iraq and Syria have failed to deter further attacks and retaliatory attacks on the Houthis may similarly prove ineffective. Moreover, engaging in military actions (such as airstrikes which the U.S. previously conducted in 2016 and are rumored to be under consideration again) against the Houthis poses a risk of undermining ongoing U.S. efforts to bring an end to the separate Yemeni conflict.
With military tools not sufficient in isolation to address the task, the administration needs to consider other mechanisms for stabilizing the region. In the short term, one measure the United States can take to lower the risk of further regional escalation, including through miscalculation or mishap, is to address the proximate cause of this flare up: the Gaza conflict.
Pushing for an immediate ceasefire in Gaza is not only a humanitarian imperative, it is critical to reducing the risk to U.S. forces in the region and thus the likelihood that the United States will be drawn deeper into conflicts it does not want. The United States needs to work harder now to stop the fighting, not just for the sake of the people of Gaza but as a matter of enlightened self-interest. Allowing Israel’s offensive to drag on for more weeks – let alone months – will only increase the chances of a bloodier, wider conflict in the Middle East directly involving the United States.
The fact that the United States finds itself on or over the threshold of new conflicts in the Middle East, despite the Biden administration’s efforts to avoid them, also highlights the inadequacies of the current U.S. legal guardrails on the use of military force. Through creative interpretations of the War Powers Resolution and the 2001 AUMF and now the 2002 AUMF as well, this White House like its predecessors has been able to involve and keep U.S. troops in wars that Congress never specifically authorized.
Although a comprehensive overhaul of the War Powers Resolution—as envisaged in the National Security Powers Act (NSPA) in the Senate and the National Security Reforms and Accountability Act (NSRAA) in the House—and reform of the 2001 AUMF not to mention repeal of the 2002 AUMF are long overdue, the near-term prospects for more ambitious legislative efforts are slim. A modest though meaningful step would be to tighten key wording in the current law. By defining what it means for U.S. armed forces to be introduced into hostilities, Congress could both force the executive branch to be more forthcoming when U.S. forces are in harm’s way and reduce the latitude of the White House to unilaterally steer the country into war.
Drawing from the NSPA, for the purposes of the War Powers Resolution the term “hostilities” would be defined as:
any situation involving any use of lethal or potentially lethal force by or against United States forces, whether or not constituting self-defense measures by the United States forces, and irrespective of the domain, whether such force is deployed remotely, or the intermittency thereof.
Such a definition would close many of the loopholes described above and help forestall future interpretive gamesmanship by the U.S. executive branch. Although by no means a war powers panacea, such a provision would meaningfully advance goals of transparency and congressional control, the objectives of the original 1973 law. The Tanker War of the 1980s, which the ongoing hostilities in the Red Sea evoke, also illustrated the shortcomings of the War Powers Resolution and led to the creation of a special subcommittee on war powers reform chaired by then-Senator Joe Biden. The current hostilities in the Middle East should similarly rouse Congress to finally enact long-needed reforms to reinforce war powers guardrails.