President Trump’s cruise-missile strike against Syria was celebrated by establishment politicians and media, their glee at striking a blow against Bashar al-Assad swamping any rational discussion of what happens next.

Assad is undoubtedly the most despicable war criminal in power today. His forces have ruthlessly starved and bombed hundreds of thousands of his own people, and tortured and executed thousands more.

But the enthusiasm to take military action against a hated leader is highly reminiscent of the run-up to U.S. interventions in Iraq and Libya. And the U.S. is even less prepared to cope with the potentially disastrous consequences in Syria.

Throughout his campaign, Trump condemned regime change, and it seemed as if he had learned from previous presidents’ mistakes. Even as late as last month, UN Ambassador Nikki Haley told reporters “our priority is no longer to sit and focus on getting Assad out.”

But after the cruise missile attack, the Trump’s administration instantaneously reversed itself. Secretary of State Rex Tillerson has said “steps are underway” to seek Assad’s removal, and Haley told CNN it is “hard to see a government that’s peaceful and stable with Assad [in power].”

What that means in real life is unclear. Trump told Fox Business News that the U.S. is not going to war with Syria, leaving observers to conclude that he either intends to have Assad removed in some other way — or to demand Assad’s removal as a part of peace negotiations like the ones taking place in Geneva.

But swiftly removing the Assad regime would have a dramatic and destabilizing effect on a country that is increasingly governed by local mafias and warlords, and where the largest opposition groups are ISIS and Al Qaeda-connected militias.

“Once the policy people look at what the day after would be — they don’t see any options,” said Josh Landis, the director of the Center For Middle East Studies at the University of Oklahoma. “The two strongest militias in Syria are Al Qaeda and ISIS, which would undoubtedly profit and would move into Damascus, were the Assad regime to be destroyed.”

Landis said that any gains made by rebel groups would inevitably lead to sectarian violence against minorities, and would have dire humanitarian consequences for the 15 million people who currently live in Assad-controlled territory.

Although the Assad regime is responsible for the majority of the hundreds of thousands of deaths in the 6-year-old civil war, rebel groups — often U.S.-armed — have also been guilty of horrific human rights violations, from abductions and torture, to mass executions and child beheadings.

Rebel violence has particularly affected Syria’s minorities, like Christians and Alawites — a Shia sect that Assad belongs to — as well as Sunnis from pro-government areas, who have been perceived as supporting Assad.

“We’ve seen that wherever rebel militias have taken Alawite or Christian regions,” Landis said, “the Alawites flee within 24 hours. There are no Alawites left, or else they’re taken captive. And Christians are gone. … That’s what’s most likely to happen in the rest of Syria if the Syrian army were destroyed.”

And if emboldened rebel groups end up fighting over Damascus — Syria’s capital city — it could force millions of minorities and middle-class Sunnis to flee, exacerbating a refugee crisis that has already led 11.6 million people to flee their homes.

The most recent and horrific massacre took place on Friday, when a car bomb likely directed by anti-government forces destroyed buses carrying mostly Shia families fleeing from pro-government towns, killing over 100 people.

“A number of people have argued with me that having a ‘Mad Max Syria’ with roving gangs or roving militias carving out bases would cause fewer deaths than Assad.” Landis said. The day-to-day body counts might go down because there would no longer be an air force, he said. “They would be restricted to shooting at each other with more conventional weapons. But that could go on for a long time.”