War Powers in Theory and Practice
Congress has abdicated by inaction
The U.S. attacks on Iran have sparked renewed debate on war powers. That debate is endless and predictable. Good lawyers can argue both sides. Believers in the unitary executive say commander-in-chief powers allows just about everything. Believers in congressional powers insist that Congress has to play a role.
Ignore the legal arguments for the moment. I believe that American historical practice sets framework for understanding the issue.
Constitution allows defense, requires vote for offense
Article IV, section 4 of the Constitution requires defense of the country and protection of the state governments.
The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence.
Note that the language does not specify who in the federal government does this, or how. In practice, Congress told the states to establish militias, now the National Guard, and wrote rules for presidents to federalize them. Congress also wrote landmark legislation allowing the military to suppress uprisings [the Insurrection Act] while otherwise barring their use in domestic law enforcement [Posse Comitatus Act].
The constitutional provisions on war were intended to deal with offensive operations against foreign enemies. Congress was given the power:
To define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations;
To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water;
To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years;
To provide and maintain a Navy;
To make Rules for the Government and Regulation of the land and naval Forces;
To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;
To provide for organizing, arming, and disciplining, the Militia, and for governing such Part of them as may be employed in the Service of the United States, reserving to the States respectively, the Appointment of the Officers, and the Authority of training the Militia according to the discipline prescribed by Congress;
It’s notable, as Justice Robert Jackson observed, that “out of seventeen paragraphs of congressional power, eight of them are devoted in whole or in part to specifications of powers connected with warfare.”
Also significant is how our first president, who was also our first commanding general and a framer of the Constitution, explained the rules. In a letter to South Carolina Governor Moultrie on August 28, 1793, President George Washington said, “The Constitution vests the power of declaring war in Congress; therefore no offensive expedition of importance can be undertaken until after they have deliberated upon the subject and authorized such a measure.”
The early Supreme Court, in Bas v. Tingy in 1800, said that Congress did not need to formally declare war to authorize hostilities and that the navy had to comply with any restrictions Congress placed on its authorizations.
While it’s clear that the Founders expected Congress to act to permit major offensive actions, later congresses accepted small scale operations. As law professor Curtis Bradley writes, in his excellent Historical Gloss and Foreign Affairs: Constitutional Authority in Practice (Harvard University Press, 2024), “The idea that presidents had the authority to protect American citizens abroad expanded over time to encompass other purported interests, including most notably commercial interests.” That’s the explanation and justification for most of the U.S. military forays into Latin America prior to the 1930s.
The United States also entered into several treaties with Latin American countries granting the U.S. the right to intervene to defend those countries from external threats or to preserved domestic tranquility.
Congress often authorized combat, rarely “war”
Look at my list of congressional authorizations for the use of force.
Most notable is the fact that only five of those occasions were declarations of war – and none since 1942. Congress deliberately chose language to authorize force, often with limitations on war aims, types of forces, or duration. Reluctance to declare “war” came from recognition that such language would give the president enormous powers, especially over economic activity. Contracts could be cancelled; communications could be controlled; defense production could be required; many normal practices of government can be suspended or revised.
Prior to World War II presidents were pretty scrupulous in their use of force. There were big debates on withdrawing U.S. troops from the Philippines, from action in the Russian civil war, and from parts of Latin America, but no laws passed to require it.
Franklin Roosevelt probably crossed the line during 1941when he authorized naval protection of convoys to Britain, but he waited until Pearl Harbor to ask for a declaration of war against Japan and until after Hitler declared war on the U.S. to reciprocate. There has been no formal declaration of war since World War II.
Korea was a mistaken precedent
In 1950, when North Korean forces attacked South Korea, President Truman missed an opportunity to ask Congress to authorize American participation in what was formally a United Nations force. Secretary of State Dean Acheson, providing a long list of earlier uses of force, didn’t think Truman had to ask Congress. As I explained in Lawfare in 2020, members of Congress were generally supportive of U.S. involvement, but leaders did not want to interrupt a July 4 recess for formal votes. By the time Congress reconvened, American forces were in combat and Truman didn’t want lawmakers to complicate any authorization of force with controversial issues like the role of Taiwan (then called Formosa).
Meanwhile, Congress was already taking action to support and fund the war both directly and indirectly. It passed an extension of the draft on June 28, a temporary appropriations bill on June 29 and a Mutual Defense Cooperation bill that included small sums for operations on the Korean Peninsula. It approved the defense appropriations bill on August 28 and a large supplemental appropriation for defense on September 22. This was business as usual for the Congress, but these actions were later cited by administration lawyers as evidence of Congress’s authorization for the conflict.
By deciding it was too much trouble to act on Korea, Congress set a dangerous precedent which allowed later presidents to act first and let lawmakers dither over taking a stand.
WPR was to prevent another Vietnam, not limited airstrikes
As my list shows, Congress did enact advance authorizations in subsequent years but felt burned when the Gulf of Tonkin resolution was treated by the Lyndon Johnson administration as the “functional equivalent of a declaration of war.” It was, but lawmakers were unhappy with how things turned out.
In the early 1970s, both opponents and supporters of the Vietnam war worked to write a law to prevent “another Vietnam,” by which they meant a large, prolonged conflict including many ground combat forces. They weren’t concerned about one-off retaliatory air strikes or rescue of Americans operations, although many members worried about “slippery slopes.”
Congress passed, over Richard Nixon’s veto, the War Powers Resolution [WPR]. [Congressional trivia: normally resolutions are nonbinding declarations of congressional opinion; a measure with “whereas clauses” is called a resolution; WPR was a joint resolution, passed by House and Senate, and enacted into law over a veto.]
Some lawmakers worried that the law gave presidents too much power since they could legally deploy forces for 45 plus days. The original law provided that Congress could end the military operations by Concurrent Resolutions not subject to presidential vetoes, but later Supreme Court decisions declared such resolutions unconstitutional. Instead, there has to be a law presented to the president for signature or veto.
WPR has worked despite flaws
I believe that the WPR has worked. Every president, despite denials that they were bound by it, has complied with the reporting requirements. Every major conflict in which U.S. forces participated – except those authorized by Congress – lasted only the 3-4 months envisioned by WPR. We haven’t had another unauthorized “Vietnam.” Military planners defined end states and exit ramps so that operations would be limited in time and scope.
On the other hand, the United States did engage in two “forever wars” in Afghanistan and Iraq on the basis of Authorizations for the Use of Military Force [AUMFs] enacted in 2001 and 2002. In the case of Iraq, the law authorized actions against Saddam Hussein to force compliance with UN Security Council resolutions. That has obviously been accomplished and several unsuccessful attempts have been made to repeal that law.
In 2001, although the White House recommended a general authorization to act to prevent terrorism, the Senate revised it to approve operations only “against those nations, organizations, or persons he [the president] determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.”
Subsequent administrations have stretched this language to cover offshoots and successors to al Qaeda throughout the Middle East. Many efforts have been made to repeal the original and language and to substitute new narrower and more specific language, but they have so far been unsuccessful for reasons given below.
Congress is too scared to act
Members of Congress are justifiably cautious about voting to approve military operations because they know there could be substantial costs in blood and treasure. Americans are willing to applaud short and successful wars, but they historically have turned against long or unsuccessful conflicts. There is a political price to be paid for supporting some wars and opposing others.
In 1991, 47 Senators opposed the war powers authorization for the war against Iraq to liberate Kuwait. After the dramatic success of U.S. and coalition forces in Operation Desert Storm – the “100 hour war” -- none of them were considered politically viable in the 1992 presidential elections. I think that explains why so many skeptical Senators like Joe Biden and Hillary Clinton still voted for war in 2002 – only to have those votes used against them in 2008.
The fear of being wrong, the fear of electoral punishment, has prevented Congress from asserting its war powers for several decades. Even if one house approved a measure of support or disapproval, Congress has failed to enact a definitive measure time and again. None on Grenada or Panama in the 1980s,none on Haiti, Bosnia, and Kosovo in the 1990s, none on Libya in 2011 or Syria in 2013. Congress did approve limitations on U.S. support for Saudi operations in Yemen, but they were vetoed by President Trump in 2019.
Congress can and should act on Iran, Israel, and Taiwan
It’s deplorable that Congress has abdicated its war powers. Members are elected to make tough decisions, not duck them or punt them to later congresses. They have an obligation to deliberate and compromise if necessary – as they do on all other vital legislation. War is too important to be left for presidents alone.
American historical practice does not require advance approval for quick, limited retaliatory air strikes. It does require it for operations likely to last for weeks, especially if ground troops are used. I don’t think it’s necessary for air operations against the Houthis, since that falls under the longstanding laws on piracy.
But if a president wants prolonged operations against Iran, Congress should vote and set conditions. The same is true regarding Israel and Taiwan, for otherwise there is no legal basis for direct U.S. combat support for either country.
Are members brave enough to do their duty? And say either yes or no or with conditions? The Framers expected Congress to do its job and the president to execute the laws faithfully. It’s about time.