How Congress Set the Stage for Trump’s Illegal War in Iran

President Donald Trump’s military campaign against Iran is an illegal and unconstitutional war. Congress did not authorize military action against Iran. The joint U.S.-Israeli airstrikes that killed Ayatollah Ali Khamenei, the country’s supreme leader, and wiped out a significant portion of the country’s political leadership and military infrastructure, were not proportionate strikes to deter an aggressor, nor were they acts of immediate self-defense.

Trump’s allies have tried to paper over this simple explanation with unpersuasive complexity. Iran, we have been told by CBS News and The New York Times, has been at war with the United States for almost 50 years since the Iranian Revolution of 1979. This is obviously not true in any meaningful sense. If it were, as The Atlantic’s Adam Serwer observed the other day, then a good portion of the Reagan administration committed treason during the Iran-Contra scandal by clandestinely selling arms to Tehran.

Nor do the administration’s actual defenses make sense. Some Trump officials have studiously tried to avoid calling it a war, apparently worried about the reaction it would cause among Americans. (Trump himself has shown no such reticence, and he does not appear to care whether the war is lawful or constitutional in the first place.) Secretary of State Marco Rubio told reporters earlier this week that the U.S. had been drawn into the war by an Israeli attack.

“It was abundantly clear that if Iran came under attack by anyone … they were going to respond and respond against the United States,” he explained on Monday. “We knew there was going to be an Israeli action. We knew that would precipitate an attack against American forces. And we knew that if we didn’t preemptively go after them before they launched those attacks, we would suffer higher casualties.”

This explanation does not suffice, either. The United States is both a superpower and the single largest supplier of military and economic aid to Israel. It can crush a smaller country’s economy without violence in the blink of an eye. The Trump administration has no shortage of means to coerce or deter Israel from attacking another country in a way that would endanger American lives. Trump and his subordinates, in Rubio’s version of events, apparently chose not to use them.

Just because Congress’s prerogatives were violated by the military campaign, however, does not mean it was blameless in this matter. Congress has chosen for many years to maintain large, perpetual standing armies that can deploy overwhelming firepower to any corner of the globe in a matter of hours. In doing so, it has upended the constitutional checks that determine when and how presidents can wage war.

For most of American history, this country did not maintain true standing armies. Conflicts like the Mexican-American War, the Civil War, and World War I were waged by a mixture of volunteers, conscripts, and/or state militia units. The U.S. Army was, outside of declared wars, a largely vestigial force compared to those maintained by European powers. Armies are expensive things to maintain, and in an age of muskets and artillery, they became more costly than ever.

The Constitution’s drafters also operated from a few basic geopolitical assumptions. In 1789, the United States consisted of 13 newly united colonies along the Eastern Seaboard. About 2.5 million Americans lived within its borders, of whom one-fifth were enslaved. A large standing army was not needed to maintain peace with the surrounding powers or to engage with Native American tribes. Alexander Hamilton, writing in The Federalist, Number 8, noted that continental European nations have unbroken land borders that require fortification and military rule to maintain.

The United States, on the other hand, had no meaningful rivals around it. “If we are wise enough to preserve the Union we may for ages enjoy an advantage similar to that of an insulated situation,” he advised. “Europe is at a great distance from us. Her colonies in our vicinity will be likely to continue too much disproportioned in strength to be able to give us any dangerous annoyance. Extensive military establishments cannot, in this position, be necessary to our security.”

The Continental Army had disbanded after the Revolution, and the United States Army that had replaced it was a token force at best. The Congress of the Confederation created the First American Regiment in 1784 with the anticipation that it would include about 700 men; it struggled to reach that size by the time the Constitution was adopted in 1789. The Framers anticipated that the bulk of American military strength would consist of the 13 states’ militias, both for practical reasons and for ideological ones.

To that end, they sought to entrench the state militias’ status in the Constitution after its ratification through the Second Amendment. “What, sir, is the use of a militia?” Representative Elbridge Gerry said, during a House debate about the Second Amendment in 1789. “It is to prevent the establishment of a standing army, the bane of liberty.… Whenever Governments mean to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise an army upon their ruins. This was actually done by Great Britain at the commencement of the late revolution.”

Fears of standing armies—and the deleterious effects that they would bring to republican society—were common in the founding era. In the Declaration of Independence, the Americans accused George III of “quartering large bodies of armed troops among us,” as well as “[keeping] among us, in times of peace, Standing Armies without the Consent of our legislatures,” and “affect[ing] to render the Military independent of and superior to the Civil power.”

One of the Founders’ principal concerns before the Revolution was Britain’s stationing of large numbers of soldiers on colonial shores. “As to the Standing Army kept up among us in time of Peace, without the Consent of our Assemblies, I am clearly of Opinion that it is not agreeable to the [British] Constitution,” Franklin wrote to an associate in 1770. Had George III raised an army from “Ireland and the Colonies” and brought it to England without Parliament’s assent, he added, “I am persuaded he would soon be told that he had no Right so to do, and the Nation would ring with clamours against it.”

Recent experience of British military occupations in Boston, New York, and other places had hardened early Americans’ views. The Boston massacre, where British troops opened fire on a crowd of colonial citizens, had been central to early narratives of independence. So too lingered cultural memories of the English Civil War, which began in part after Charles I tried to use the army to intimidate and suppress Parliament, and Oliver Cromwell’s Protectorate that followed it, which had ruled the British Isles as a military dictatorship.

The English experience was hardly ancient history to the founding generation; it was roughly as distant to them as World War I is now to us. As the Framers set out to craft a wholly republican constitution for the new nation, they were particularly sensitive to military rule in ancient republics like Greece and Rome. But as the revolutionary cause had been launched in part to preserve what the Founders saw as inherent liberties and freedoms derived from long English tradition, fear of military rule became paramount.

George Washington’s farewell address, for example, is well remembered for its advice to avoid foreign entanglements and preserve the Union. If the states turned against one another, he warned, they would be forced to maintain armies against one another and become pawns of foreign intrigues. Preserving the Union would, Washington explained, “avoid the necessity of those overgrown military establishments which, under any form of government, are inauspicious to liberty, and which are to be regarded as particularly hostile to republican liberty.”

This association between standing armies and despotism also influenced the structure of the Constitution. Though the president is commander in chief of the armed forces, he is not their sole master. Congress alone can “raise and support armies,” and it can do so for no more than two years at a time before they must be reauthorized. It can “make rules for the government and regulation” of the military, and it is responsible for laying out the rules that govern when and how the militia can be used in federal service.

Much of the focus of Congress’s war powers today is on the specific power to declare war itself. This is a vital and important check, but it is not the only one. Until the twentieth century, presidents needed Congress’s approval to wage war—both to declare it as a matter of legality and to fund it as a matter of practicality. A president could not truly wage war without Congress until the mid-twentieth century because they had no real forces at their command. Funding, not authorization, is the real source of Congress’s power over the military.

“The legislature of the United States will be OBLIGED, by this provision, once at least in every two years, to deliberate upon the propriety of keeping a military force on foot; to come to a new resolution on the point; and to declare their sense of the matter, by a formal vote in the face of their constituents,” Hamilton wrote in The Federalist, Number 26. “They are not AT LIBERTY to vest in the executive department permanent funds for the support of an army, if they were even incautious enough to be willing to repose in it so improper a confidence.”

Though Hamilton does not say it outright, the two-year spending limit is a subtle but clever bit of constitutional design. Even if Congress decides to fund a war, it cannot do so beyond the next election in the House of Representatives, which also takes place every two years. This too has its roots in English history. As I’ve noted before, Congress’s general power of the purse grew out of the long history of taxation squabbles between the English monarchy, which often sought to wage war, and Parliament, representing the nobles and gentry who could obtain greater freedoms in exchange for funding it.

In a post–World War II era, however, this framework has broken down. Warfare in the twentieth and twenty-first centuries bears little to no resemblance to warfare in the eighteenth and nineteenth centuries. No longer was combat waged simply by rifles and cannons, or by large groups of infantry and cavalry. Now it required an industrial base that could supply tanks, airplanes, and other heavy machinery. With greater scientific advancement came greater destructive power. A single U.S. aircraft carrier can overthrow a medium-size nation’s government.

Americans have now grown used to standing armies in the post–World War II era, when they could be justified by the Cold War and its associated conflicts. The fall of the Berlin Wall and the demise of the Soviet Union did not return things to normal; U.S. leaders soon claimed that their post-1991 supremacy justified a greater American presence on the world stage. After the September 11 attacks, politicians from both parties treated global military power—and the immense resources necessary to support it—as a necessity.

I do not mean to offer a comprehensive overview of modern American military history and foreign policy. Nor do I mean to suggest that some U.S. deployments overseas are unnecessary or undesirable, or that the U.S. should abandon its commitments to NATO allies or its Asian-Pacific partners. All I wish to note is that it is now unthinkable for most Americans and nearly all of our federal elected officials to have anything other than millions of men and women in permanent military service, a dozen aircraft carriers, a massive air force, and hundreds of bases around the world.

The United States, through its elected representatives, made a conscious choice after 1945 to not demilitarize itself as it had after previous conflicts. It made a conscious choice after the Vietnam era to abandon the draft in future conflicts and opt for an all-volunteer force, further separating civilian and military societies from each other. And it has made conscious choices after the Gulf War, the Afghanistan War, and the Iraq War to keep ramping up military spending in the absence of a major adversary. Americans, via Congress, have decided—perhaps without actively realizing it—to create and maintain the standing army that their ancestors had long feared.

When Trump took power again last year, nobody seriously argued against changing course. The president requested more than $850 billion for the military, and Congress responded by handing him $8 billion more than he had requested. It was not a matter of party control, either: Both the House and the Senate approved military funding by wide bipartisan margins. In doing so, they handed him a broad mandate to wage limited wars like the one he launched against Venezuela last year and Iran this year. (Do not bother pondering the never-used War Powers Act, which is basically a fig leaf for Congress’s abdication at this point.)

None of this changes the fact that Trump is still constitutionally required to seek Congress’s approval, or that the war he launched is illegal and therefore an impeachable offense. But Congress itself shares a measure of the blame. Nothing that Trump did was possible without its support and funding, as well as the choices that past generations of American leaders have made. If Congress wants to truly reassert itself, it could follow in its ancestral footsteps by turning down Trump’s request for even more funding to keep waging the war. In the modern age, that is the truest test of congressional approval.