Erik Cox Photography / Shutterstock

How Can Congress Authorize War When It Can’t Decide What War Is?

There’s bipartisan agreement that the law governing America’s wars needs an update. There’s also bipartisan agreement that it won’t happen anytime soon.

In the past few years alone, the U.S. has launched military strikes in Syria, Somalia, Yemen, and Iraq—all in the name of fighting al-Qaeda and its later offshoot, the Islamic State. For the most part, Congress has accepted this. But as Trump-administration officials talk ever tougher about Iran, many Capitol Hill Democrats, and some Republicans, fear that the confrontation could spin out of control into a devastating conflict. And now they’re trying to claw back some of the power that the president—whom they view as dangerous and reckless—has to declare war.

Administration officials such as Mike Pompeo have made the rounds to argue for the connection between Iran and al-Qaeda. The president declares he wants to negotiate with the Iranians in one breath and threatens consequences the likes of which no one has ever seen in the next. This worries Democrats such as Representative Jason Crow of Colorado, a former Army Ranger who served in Iraq and Afghanistan. “I learned firsthand,” he said recently, “that when politicians talk tough in this town, real people get hurt.”

He’s one of 87 co-sponsors of a bipartisan amendment to the House defense budget that would prohibit Donald Trump from launching a war with Iran without congressional authorization. Elissa Slotkin, a freshman Democratic House member from Michigan who served in Iraq with the CIA, is another. When she heard Pompeo talking about al-Qaeda and Iran this summer, she said Saturday at the Aspen Security Forum, “my ears pricked up.” It sounded to her as if Pompeo was trying to create space to go to war with Iran, and argue that the administration could legally do so under the 2001 law that authorized military force against al-Qaeda and its associated forces.

No one who voted for that law after the September 11, 2001, attacks would have envisioned its use against the Islamic Republic of Iran, she said. Her colleague Mac Thornberry, the ranking Republican on the House Armed Services Committee who voted for the authorization, said at the same event that he certainly didn’t envision all the battles the law is currently being used for—including the fight against ISIS and other counterterrorism missions all over the world.

Related: Pentagon Official: We Didn’t Link Iran to al-Qaeda In Hill Briefings

Related: Iran Briefings Leave Congress Divided Over Trump’s Intentions, War Powers

Related: The US Military Held an American as an Enemy Combatant for Over a Year. Here’s What That Means.

But this is also why it has proved so hard to change, despite seemingly bipartisan agreement that it needs an update. The law authorizes virtually all of America’s counterterrorism work overseas, and if it simply goes away without being revised, those missions are arguably illegal. But, Slotkin said, there are wide disagreements on what, if anything, should replace it. Some members don’t want to authorize anything. Some members want to build in restrictions other members find unacceptable. Some want to keep things exactly the same. “We’ve got 50,000 forces in the Persian Gulf right now,” Slotkin said. “If we took away the authorization of military force—every authorization—right now, what would we do? Would we pull them all back by the letter of the law? We’d have to examine that.”

The debate isn’t just about an 18-year-old law; it involves much bigger questions about constitutional powers, and war and peace. These are questions members of Congress acknowledge, but have so far declined to really answer with a debate and a vote. Thornberry himself posed some of them: “When is it war that Congress has to approve? When is it self-defense?” Would Congress have to authorize U.S.-military escorts for tankers through the Strait of Hormuz? What about shooting down another country’s drone? What about cyberattacks?

In the meantime, Slotkin said, she and her co-sponsors felt it necessary to at least lay down a marker that Congress wants to exercise oversight.

But despite suspicions that Pompeo is trying to build the case to use the 2001 authorization against Iran, it’s not clear the administration would even go that route. Pompeo and his Iran adviser Brian Hook have dodged questions about this in open congressional hearings, saying only that whatever action they took with Iran would be under their legal authority. But Mark Esper, Trump’s nominee to be secretary of defense, said at his confirmation hearing that the 2001 authorization would not apply to Iran. Instead, he said, the president had the authority under Article II of the Constitution as commander in chief. “I don’t think there’s a serious attempt to use [the 2001 authorization] for that purpose,” Thornberry said Saturday. “I don’t think anyone would support it.”

The amendment Slotkin co-sponsored would not prevent a strike on Iran in self-defense, which is the likeliest justification Trump would claim for a strike if he did order one. When National Security Adviser John Bolton announced in May that the U.S. was sending a carrier strike group to the region in response to intelligence about Iranian threats, he warned of “unrelenting force”—but in the event “of any attack on United States interests or those of our allies.”

A similar measure failed in the Republican-dominated Senate. The Democrat Chris Murphy of Connecticut expressed disgust at what he called Congress’s abdication of responsibility to declare war in numerous theaters where the United States has recently entered into armed hostilities—in Libya in 2011, and against ISIS in Iraq and Syria in 2014. “We have given up on authorizing military force largely because it’s a lot harder than it used to be,” he said at an earlier event at Aspen. “We don’t have armies marching against each other; we don’t have peace treaties that wrap up hostilities. It’s harder to define your enemies. It’s much harder to define what victory looks like. And we just stopped doing it.”

Murphy noted that Barack Obama was widely seen as weak for failing to strike Syria after President Bashar al-Assad used chemical weapons against civilians in 2013, stepping over a “red line” the president had set the year before. Instead, Obama went to Congress, which did not authorize such a strike, and Obama backed off. Murphy said he was right to do so. “Because you can’t get authorization is not an excuse to violate the Constitution,” he said.

The 2001 authorization for the use of military force against al-Qaeda is in some sense a remnant of the forever wars in Iraq and Afghanistan, launched when the horrors of 9/11 were still raw. Nearly two decades and thousands of U.S.-military deaths later, the appetite for new overseas interventions is low even as old ones drag on. Some 60 percent of Americans, according to a Reuters/Ipsos poll from May, would oppose a preemptive strike on Iran—but 79 percent said the U.S. military should respond if Iran attacked.

More than half expected war within the next few years regardless. In the end, it’s Trump’s aversion to open-ended military adventurism that might prove a stronger brake on any possible confrontation with Iran than a 20-year-old law—or anything else Congress does, for that matter.