Analysis: Trump risks retaliation in conflict he sought to avoid.

Last week, President Donald Trump promised to withdraw from Syria. This week, he opened a new front against Syrian leader Bashar Assad that risks drawing the U.S. into a broader conflict there.

By attacking Assad late Friday, the Trump administration sought to warn the Syrian leader against continuing to use illegal chemical warfare agents, following the gassing of civilians near Damascus last weekend.

The administration calculated that the need to send a signal to Assad over chemical weapons outweighed the possibility of provoking a response from his allies, Russia or Iran, on the battlefield in Syria, elsewhere in the Middle East or even in cyberspace.

The risk, analysts say, is that the U.S. would then end up in a cycle of escalation that entangles the American military more deeply in the Syrian conflict than the administration intended.

“Given the linkage between Russia, Iran and Assad, an attack that we would consider limited and precise might be misconstrued by one or more of those three parties and justify from their perspective a retaliatory strike,” said retired U.S. Army Lt. Gen. James Dubik, a senior fellow at the Institute for the Study of War. “Then what do we do?”

Possible scenarios for a retaliation include attacks by Iranian-backed militias against U.S. forces in the Middle East, stepped-up incidents against U.S. forces and their allies within Syria or “asymmetric responses” such as cyberattacks entirely outside the theater itself. It remains unclear whether the strike will prevent Assad’s forces from turning to chemical weapons in the future as the leader seeks to extend his reach across the country while consolidating gains in the civil war.

Robert Ford, a former U.S. ambassador to Syria and fellow at the Middle East Institute and Yale University, said military action would deter Assad’s forces from using chemical weapons only if the U.S. conducts follow-up strikes when new atrocities occur.

“I don’t think, in order to make the deterrent stick, that this can be the last attack,” Ford said. The former U.S. diplomat, who said Assad’s forces were using chemical weapons in part because they lack manpower, predicted the Syrian leader “will test us — and we will have to do this again.”

Trump promised that the strikes wouldn’t necessarily be a one-off. “We are prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents,” the president said in an address at the White House late Friday night.

Some who support the strikes say that even if they fail to prevent Assad from using chemical weapons in the future, they will send the message that the international community is watching and intends to enforce the ban on chemical weapons that countries instituted after World War I.

British Prime Minister Theresa May said the strikes, which the U.K. and France participated in, would “send a clear signal to anyone else who believes they can use chemical weapons with impunity.” Referring to the recent nerve-agent attack on a former Russian spy living in Salisbury, England, she said, “We cannot allow the use of chemical weapons to become normalized — within Syria, on the streets of the U.K. or anywhere else in our world.”

But the military intervention also comes as Washington has all but given up on seeking the removal of Assad more than seven years into Syria’s civil war. Trump wants the Pentagon to withdraw U.S. troops after the Kurdish-led militia Washington is backing in Syria finishes off the remnants of the Islamic State terror group.

The departure of U.S. troops, military strategists say, will likely pave the way for Assad’s consolidation of control in the country, backed by Russia, Iran and the Lebanese militia Hezbollah.

The result is what Defense Secretary Jim Mattis described in congressional testimony on Thursday as “contrary impulses.” On the one hand, Trump wants the U.S. to have nothing to do with Syria. On the other, he wants to dictate norms of behavior on Syria’s battlefield that upset him when violated.

Those who take a dim view of selective strikes in response to chemical weapons usage say the U.S. has given up trying to ensure the departure of Assad, which means his forces will continue to kill whomever they wish as they consolidate control, even if they do so with conventional weapons.

“As long as you have a strategy that leaves Assad in place and allows him to slaughter his people as he sees fit, he is going to do so,” said Kenneth Pollack, a former CIA analyst and resident scholar at the American Enterprise Institute. “And he is probably going to use chemical warfare agents.”

But for Washington to stop Assad from killing his own citizens more broadly, “we’re getting closer to a regime-change scenario because he’s bombing almost every day,” said Ford, the former U.S. ambassador. “To me, that’s drawing us in. I have zero confidence that we could control where that goes then.”

Pollack suspects that the Syrian regime and Iran won’t retaliate against the U.S. because they are ascendant on a battlefield that Trump has promised to leave, and they won’t want to engage in any action that could prevent a U.S. departure that would amount to a big win for them. Russia could have more of a motive to retaliate, Pollack said, even though before last year’s attack on Assad’s airfield, U.S. forces warned Russia in advance.

“Russia is the wild card out there,” Pollack said, because President Vladimir Putin’s interests are bigger than Syria. “They are about how much [the U.S. is] allowed to act unrestrained and how much does he want to demonstrate that he can fight back.”

The strike also raises thorny questions for Trump administration officials about why they are willing to intervene when Assad uses chemical weapons against civilians but won’t act in instances where his forces are killing far more with conventional weapons.

“How horrific is it that we are particularly disturbed by one way of killing Syrian children but not the other?” asked Mara Karlin, a former top Pentagon official during the Obama administration and an associate professor at the Johns Hopkins School of Advanced International Studies.

The allure of such strikes, Pollack said, is that they are “feel-good military operations,” which make the American public think they have done something to help Syrians.

“No we didn’t,” Pollack said. “Five hundred thousands of them have died, and we’ve done nothing.”