The MQ-9 Reaper attack that took out Iranian General Qassim Suleimani was a drone strike for peace, President Trump explained last week: we took action “to stop a war. We did not take action to start a war.” That’s a theory, and it’s going to be put to the test. “All is well!” the president tweeted last night as a salvo of Iranian missiles fell on U.S. positions in Iraq: “So far, so good!”

Trump’s decision to target Suleimani—a figure described as the Iranian equivalent of “an American Vice President, chairman of the Joint Chiefs and CIA director rolled into one”—wasn’t the first time the U.S. government has aimed lethal force at a top government official. There’s the checkered—and occasionally absurd—history of the CIA’s Cold War assassination attempts, including the Kennedys’ efforts to kill Fidel Castro. But we’ve also gone after legitimate targets in congressionally authorized wars: the downing of Admiral Yamamoto’s plane in WWII and the attempted decapitation strike against Saddam Hussein at the start of the Iraq War.

The Suleimani killing was something new under the sun. It marked the first time an American president has publicly ordered the assassination of a top government official for a country we’re not legally at war with.

This is where you’re supposed to acknowledge that the Quds Force commandant was an evil guy who got what he deserved. Done. But that’s got nothing to do with whether the move was wise or constitutionally permissible.

U.S. forces took out Suleimani “at the direction of the President,” per the Pentagon’s announcement. On what authority, exactly? For now, the official rationale is classified. In terms of public justification, all we have is some hand-waving by Trump’s national security adviser about the president’s “constitutional authorities as commander in chief to defend our nation” and the 17-year old Authorization for the Use of Military Force in Iraq (2002 AUMF). Neither comes close to vesting the president with the power to set off a whole new war.

The 2002 AUMF authorizes the president to use military force in order to “defend the national security of the United States against the continuing threat posed by Iraq” and enforce various UN resolutions “regarding Iraq.” Unless “45” is going to break out the presidential sharpie and change the “q”s to “n”s, that’s not going to cut it. Neither will the 2001 AUMF, as I’ve explained at length elsewhere (See: “Repeal Old AUMFs and Salt the Earth”).

If and when the administration deigns to reveal its legal theory, the argument will probably be: (1) the AUMFs license our continuing presence in Iraq; and (2) the president has inherent power under Article II to defend our personnel from the sort of attacks Iranian proxies have carried out in recent weeks. (National Review’s David French outlines that theory here.)

How far up the escalation ladder are these powers supposed to extend, however? “Supreme Leader” Ayatollah Ali Khamenei sits atop the military chain of command and apparently had to approve the recent militia attacks. Does Article II empower Trump to order a hit on the Ayatollah? That we wouldn’t miss that guy either seems rather beside the point.

It’s true that Article II leaves the president with some defensive war powers, allowing him to “repel sudden attacks,” as Madison’s notes from the Convention put it. But as we move up the ladder, at some point we’ve left the realm of self-defense and the response becomes in effect, a declaration of war. The Constitution vests that power in Congress.

War powers practice in the early republic suggests that the president’s power of “self-defense” was far narrower than Trump’s defenders imagine. During our first four presidential administrations, the U.S. was on the receiving end of multiple acts of war, including “invasions of territory (Creek [Indians]), illegal capture of neutral shipping not carrying enemy contraband (England and France), and the kidnapping of thousands of foreign sailors (England).” Yet, as the University of Virginia’s Sai Prakash explains, “even though [those] nations had declared war on the United States in formal and informal ways, Presidents Washington, Adams, Jefferson, and Madison believed that the President could not wage war in response.” Without formal authorization from Congress, early presidents recognized that “they were limited to those steps falling short of a declaration of war, such as defensive measures.” As Washington put it in 1793,

“The Constitution vests the power of declaring war with Congress; therefore no offensive expedition of importance can be undertaken until after they shall have deliberated upon the subject, and authorized such a measure.”

In his June 1, 1812 message to Congress, President James Madison outlined a long train of abuses committed by the British: they’d “wantonly spilt American blood within the sanctuary of our territorial jurisdiction” and ripped “thousands of American citizens… from their country and from everything dear to them,” forcing them into the service of the empire. “We behold, in fine, on the side of Great Britain, a state of war against the United States, and on the side of the United States a state of peace toward Great Britain,” Madison declared. But whether the United States could answer those abuses with war “is a solemn question which the Constitution wisely confides to the legislative department of the government.”

Even James K. Polk understood that just drawing enemy fire wasn’t enough to get a war started. You could, as Polk did, gin up a pretext for one by sending U.S. troops into disputed territory and getting some of them killed, but to “take the fight to the enemy,” you needed authorization from Congress.

All this is likely “academic.” The White House likely doesn’t consider itself bound by its own Office of Legal Counsel opinions, much less the original meaning of the Constitution’s war powers provisions.

But what recent events have made plain, as Jack Goldsmith sums up, is that

“Our country has, quite self-consciously, given one person, the President, an enormous sprawling military and enormous discretion to use it in ways that can easily lead to a massive war. That is our system: one person decides.”

I’d quibble with “self-consciously,” otherwise, as a descriptive matter, that’s right: that’s the system we’ve got. And it’s the inverse of the one the Framers designed: “This system will not hurry us into war,” James Wilson told delegates to the Pennsylvania ratifying convention in 1787, “it is calculated to guard against it. It will not be in the power of a single man... to involve us in such distress, for the important power of declaring war is vested in the legislature at large.”

As of this morning, things looked brighter than they did for several harrowing hours last night. Iran’s response didn’t result in any American deaths, perhaps by design: “We do not seek escalation or war,” tweeted Foreign Minister Javad Zarif. Trump may be inclined to deescalate as well. Cooler heads may yet prevail.

It is, however, insane and intolerable that peace depends on the restraint of the Islamic Republic and an American president given to rage-tweeting war-crime threats. No one fallible human being should be entrusted with the war powers now vested in the presidency. Now, more than ever, Congress needs to do everything in its power to reclaim its authority over war and peace.

This article first appeared at the Cato Institute.

Image: Reuters.