Call it a forever war.

US troops are fighting ISIS in Syria. But Congress hasn’t approved it, the public hardly knows about it, and it’s not clear under what conditions the US would leave.

Americans tend to only be reminded of the 900 US troops and hundreds of contractors stationed there when they came under attack, often from militants who have Iran’s support, or when there is a mishap — like this week.

In northeast Syria on Sunday, 22 US soldiers from an elite commando unit were injured in a helicopter’s “hard landing” due to a technical issue, according to the Pentagon.

More broadly this spring, US bases have been coming under attack from Iranian-backed groups, with the potential for the US troops there to be drawn into a broader conflict.

The US is in Syria to curb the terrorist group Islamic State or ISIS, in a region that is semi-autonomous and run by the Syrian Democratic Forces, a Kurdish group.

Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, has said that troops are needed because “if you completely ignore and turn your back, then you’re setting the conditions for a resurgence.”

But experts say that the US troops there are not building toward a sustainable outcome, and that resisting ISIS has become the pretext for a perpetual US presence.

“It’s a strategy that just makes no sense,” says Robert Ford, who served as US ambassador to Syria from 2011 to 2014. “The real way forward is not leaving 900 troops to play whack-a-mole in eastern Syria.”

Ford explains that the American mission to secure the outright defeat of ISIS is impossible. The 900 troops in the northeast of Syria and the US garrison at al-Tanf cannot stop a low level of recruitment into ISIS ranks. “So we can bomb some and we can kill some, but they’ll always replace the people that they lose,” he told me. “This is a classic forever war.”

Why the US is in Syria

The Biden administration says its Syria policy is working. “I take objection to the notion of a forever war,” a senior Pentagon official, speaking on the condition of anonymity, told me. “US forces are present on the ground focused on only one mission, and that is the enduring defeat of ISIS.”

Yet the risk of the conflict expanding persists. The US and Iranian-backed forces keep coming into conflict in Syria.

On March 23, an Iranian-backed group sent a drone to a US-led coalition base near the northeastern Syrian city of Hasakah. The drone self-destructed and killed an American civilian working as a mechanic on the base, and injured five US servicepeople and another contractor. In response, Biden ordered strikes against three targets connected to Iran’s Islamic Revolutionary Guards Corps, who then retaliated further the next day.

That tit-for-tat shows that Syria is where all of the US’s muddled policies toward the Middle East collide. The US began supporting Syrian rebels soon after the country’s civil war broke out in 2011. President Barack Obama sent Americans to train those rebels to fight ISIS in neighboring countries. (ISIS’s rise was a spillover effect of the now-20-year-old US invasion of Iraq, and compounded by the effects of the Syrian civil war). As part of that campaign, the US partnered with Kurdish fighters from a semi-autonomous enclave, and to this day supports them, much to the anger of the US’s NATO ally Turkey. Meanwhile, the US’s close partner Israel bombs Syrian sites without acknowledgment, and Russia is supporting the Syrian regime.

The core US interest here is making sure that ISIS cannot launch attacks on the US or Europe. As of now, it cannot. ISIS’s capacity is “significantly degraded,” according to Department of Defense Inspector General reports. The terrorist group in 2019 was “territorially defeated” and it is “unable to threaten regional security and Coalition homelands,” meaning the US interest here has largely been accomplished.

But the mission is also impossible insofar that new ISIS fighters are still being recruited, and the US military alone simply cannot address what’s much more than a military problem.

One of the complicating factors keeping the US in Syria is the temporary camps in al-Hol, Syria, where about 50,000 people reside. The site has for decades been a refuge for displaced persons, and is nominally run by US-backed fighters. Today many residents are believed to be family members of ISIS. Residents aren’t free to leave, and al-Hol represents a significant legal and humanitarian challenge. “It’s approaching conditions that amount to de facto detention under international human rights law, but it’s importantly not a detention center, because no one there has been accused of or charged with a crime,” says Mara Revkin of Duke Law School, who has visited the camps as part of her research. Few countries in Europe want to repatriate their residents from other countries and neither do Middle Eastern countries, so tens of thousands of people are caught in between.

The security situation is already precarious after several ISIS jailbreaks. ISIS has threatened to attack al-Hol. The Syrian Democratic Forces also maintain several prisons of ISIS fighters and would have a hard time overseeing those detention facilities and camps without US support.

Meanwhile, more than a decade since he brutalized peaceful protests against his regime and officiated over the country’s ongoing civil war, Syrian President Bashar al-Assad is still in power. He is without question a war criminal, and is effectively being welcomed back into the Arab government fold.

All of this has led to inertia. In 2019, President Donald Trump announced that the US would withdraw from Syria. But lawmakers, military leaders, and many in the media called it a betrayal, and Trump ultimately changed his mind. Biden’s team initially reviewed its Syria policy, though it’s difficult to parse out any shifts.

“I don’t think that there is much reason to believe that America remaining longer there is somehow positioning us for an exit on better terms, or it’s going to leave Syria in a shape that’s more favorable to US interests,” Sam Heller, a researcher with Century International, told me. “The lowest effort option in Syria is to just continue on autopilot.”

And Syrian civilians are among those suffering the most.

Is this an illegal war?

The legal basis for the US in Syria remains sketchy, and members of Congress want more clarity.

In a March hearing, Rep. Sara Jacobs (D-CA) asked about the need for a formal authorization from Congress permitting US troops there. The Biden administration has told Congress that the “83 separate times” since 2021 that the US in Iraq and Syria has come under Iranian-backed militias’ attacks were “too episodic to constitute the kind of ongoing and continuing hostilities that would trigger Congress’s constitutional war powers,” according to Jacobs.

At a certain point, 83 episodes starts to sound like a trend. So she asked Milley about why the conflict doesn’t merit more congressional oversight.

But Milley, the country’s top uniformed general, dodged the question. “I’m not a constitutional lawyer on those issues,” he said. He emphasized that Iran wants to push the US out of Syria and said the mission is worthwhile.

The legal and strategic rationale makes the conditions under which the US would depart murky.

US troops are there under a 2001 authorization of military force that Congress passed in the days after the September 11 attacks to counter al-Qaeda. The Obama administration had determined that ISIS is a successor to al-Qaeda. The senior US defense official told me that the government of Iraq sent a letter to the UN in 2014 requesting US and international help in response to the terrorist threat from Syria. Meanwhile, the justification for counter-strikes against Iranian-backed groups falls under the Constitution’s Article 2 as a form of self-defense.

Experts say it’s an overly broad interpretation. “The Biden administration has relied, in my view, very problematically on its claimed inherent constitutional authority,” says Katherine Ebright of the Brennan Center.

What next for the US in Syria

The Biden administration has doubled down on maintaining US troops in Syria. “The US has no intent to withdraw in the near future,” the senior Pentagon official told me. “We successfully pushed ISIS out of the territory it once held, but there are still ISIS members in Iraq and Syria, and we have more work to do.”

Nine-hundred troops, Biden’s team argues, is a light footprint and shows that the US has learned from the wars in Afghanistan and Iraq that a large garrison occupation is a liability. But they are still in harm’s way, and it’s not something Congress has approved.

“There’s just no exit,” Simone Ledeen, a former senior Defense Department official from the Trump administration, told me. “We can’t just stay there indefinitely, with no strategic end-state. It’s untenable.”