
In the early hours of Feb. 28, President Donald Trump initiated a military campaign against Iran alongside Israel: Operation Epic Fury. The attack on Iran, which as of writing has sparked a conflict stretching from Cyprus to the Indian Ocean, was undertaken without any prior congressional authorization. Despite the U.S. Constitution purposefully allocating the power to declare war and related authorities to Congress to provide an “effectual check to the Dog of war by transferring the power of letting him loose from the Executive to the Legislative body” (in the words of Thomas Jefferson), Trump unilaterally unleashed the dogs of war.
Congressional opponents of Trump’s unauthorized war face daunting challenges in collaring the hellhound he’s unchained and ending U.S. hostilities. The constitutional scheme in which the legislature must affirmatively vote to go to war has been upended. Now, Congress must instead vote to stop a war the president has already unilaterally started and indeed must be able to override a presidential veto to do so with legal force. The Senate and the House held such votes on Trump’s Iran war this week, but both were narrowly defeated in their respective chambers.
Congress, however, has another tool, what has sometimes been called the ultimate war power: the power of the purse. The Trump administration reportedly intends to seek supplemental appropriations to fund the war on Iran—a conflict which cost an estimated $11 billion in just the first four days. In contrast to war powers legislation to block further hostilities that requires affirmative action by Congress, mere congressional inaction on appropriations by itself may serve as a restraint.
Should the Iran war continue, blocking or restricting appropriations presents a potential source of leverage for Congress to curtail further executive warmaking. Conversely, appropriating funds while the fighting continues may not only facilitate these unnecessary hostilities, but if the funding were clearly specific to ensuring these hostilities can continue, doing so risks legally authorizing them.
Funding Restrictions and Unauthorized War
Congress has a long and mixed record of curbing funding to restrict unauthorized hostilities by the White House. (The Congressional Research Service has a number of excellent reports analyzing this history.) Such restrictions can take two basic forms. First, Congress can simply refuse to enact appropriations and use legislative inaction to block requested funding. Second, Congress can attempt to enact specific funding restrictions or prohibitions through affirmative legislation. Such legislation is, however, subject to presidential veto (which would require supermajorities of both chambers to overcome).
In the last several decades, Congress has sometimes succeeded in enacting such funding restrictions on U.S. military operations undertaken without prior congressional authorization.
After the 1971 repeal of the Gulf of Tonkin Resolution—the authorization for the Vietnam War and other conflicts in Southeast Asia—the Nixon administration continued hostilities in the region. Congress ultimately terminated them—specifically President Richard Nixon’s unauthorized bombing campaign of Cambodia, Operation Freedom Deal—through funding cutoffs in 1973. Section 307 of P.L. 93-50, which went into effect on Aug. 15, 1973 provides that:
None of the funds herein appropriated under this act may be expended to support directly or indirectly combat activities in or over Cambodia, Laos, North Vietnam, and South Vietnam by United States forces, and after August 15, 1973, no other funds heretofore appropriated under any other act may be expended for such purpose.
This provision represented a compromise between Congress and the White House in the face of a looming government shutdown after Nixon vetoed an earlier supplemental appropriations bill which included an immediate funding prohibition.
In 1994, Congress also enacted funding restrictions to ensure the withdrawal of U.S. forces from Somalia. Section 8135 of the DOD Appropriations Act for Fiscal Year 1995, P.L. 103-335 provides that, “None of the funds appropriated in this act may be used for the continuous presence in Somalia of United States military personnel, except for the protection of United States personnel, after September 30, 1994.”
That year, Congress also enacted funding restrictions with respect to U.S. military operations in Rwanda. P.L. 103-335 provides that, “No funds provided in this act are available for United States military participation to continue Operation Support Hope in or around Rwanda after October 7, 1994, except for any action that is necessary to protect the lives of United States citizens.”
Skipping forward to today, legislation to reform the 1973 War Powers Resolution in order to give that law real teeth—the National Security Powers Act in the Senate and the National Security Reform and Accountability Act in the House—would impose automatic funding cutoffs for unauthorized military actions by the White House. Although these long needed reform measures were introduced on a bipartisan basis, neither has received a vote.
Inaction on a Supplemental to Curb the Iran War
In principle, the Trump administration’s expected request for supplemental appropriations provides Congress with powerful leverage to curtail unauthorized hostilities. In its most blunt form, Congress could simply refuse to appropriate additional funds for the war.
In that case, inaction could potentially force practical constraints on hostilities against Iran. A supplemental funding bill would require 60 votes in the Senate for passage – given there were 47 votes in favor of affirmatively ending the president’s use of armed force against Iran in the recent War Powers Resolution vote, opponents of these hostilities have a real chance of defeating a supplemental appropriations bill.
By playing hardball, Congress could force the White House to more seriously look for offramps from the conflict it started. Of course, the enemy gets a vote and Iran may not be prepared to declare “enough.” (The administration may, in such a scenario, also have to use its considerable leverage over Israel to ensure its partner in this war also ceases hostilities.) But Congress needs to put meaningful pressure on the president to bring his unnecessary war to a close.
For his part, the president has yet to articulate clear goals for the conflict, let alone a clear endgame. Indeed, he has reportedly even shown interest in escalating further by putting boots on the ground. But he campaigned on ending forever wars, and may also feel political pressure to find a way out given the early loss of U.S. service members, the economic impacts, and the domestic unpopularity of the war.
Using a Supplemental Request to Enact Iran War Funding Restrictions
Depending on the precise supplemental funding request from the administration, Congress could also seek to impose specific funding restrictions. This could include, for example, prohibitions on “combat activities in, over, or against Iran” with an exception for the interception of incoming Iranian attacks.
Another alternative could be using funding restrictions to sunset the conflict by some future date,as Congress did in 1973 with Nixon’s Cambodia bombing campaign.
Once again, any such affirmative legislative action—as opposed to congressional inaction of simply refusing to appropriate funds—would be subject to presidential veto. That said, if the executive branch needs the funds to keep fighting its war, it may be more likely to acquiesce to congressional restrictions or a sunset.
The Consequences of Congress Providing Funds Specific to the Iran war
Conversely, if Congress were to enact supplemental appropriations without restrictions, the legislature would not only be facilitating the continuation of this unnecessary conflict but also potentially providing the legal imprimatur it currently lacks.
Supplemental appropriations could also allow the White House to circumvent the time limits imposed by the War Powers Resolution for unauthorized hostilities. The War Powers Resolution contains a 60-day termination provision, requiring the withdrawal of U.S. forces from any unauthorized hostilities unless Congress steps in to authorize the military operations. In the view of the executive branch (as articulated in 2000 by a Department of Justice memo), sufficiently specific appropriations can constitute such an authorization and thus allow the White House to continue using military force notwithstanding the War Powers Resolution’s 60-day clock.
In 1999, the Clinton administration was able to continue its congressionally unauthorized Kosovo military intervention (Operation Allied Force) beyond that time limit because (in the view of the executive branch) Congress subsequently provided sufficiently specific funding.
Conclusion
The Constitution’s division of war powers between Congress and the president is currently in abeyance with a majority in the legislature shirking its duties with respect to the use of force and the White House all too happy to usurp those authorities. The power of the purse is one of the few mechanisms available to the minority in Congress (specifically in the Senate) who oppose further unnecessary and imprudent presidential warmaking to put real pressure on the executive. If the president’s Middle East war continues and the administration seeks additional funds for it, members of Congress seeking to restore the constitutional order must be prepared to use this tool.
– Brian Finucane, Published courtesy of Just Security.

