President Donald J. Trump was right to strike at the regime of Syrian President Bashar al-Assad for using a weapon of mass destruction, the nerve agent sarin, against its own people. Mr. Trump may not want to be “president of the world” but when a tyrant blatantly violates a basic norm of international conduct — in this case, the ban on using chemical or biological weapons in armed conflict, put in place after World War I — the world looks to America to act. Mr. Trump did, and for that he should be commended.
The real test for Mr. Trump is what comes next. He has shown a total disinterest in working to end Syria’s civil war. Now, the administration has leverage it should test with the Assad regime and Russia to restrain Syria’s air force, stop any use of chemical or biological weapons, implement an effective cease-fire in Syria’s civil war and even move toward a negotiated transition of power — goals that eluded the Obama administration.
At the same time, it must prevent or mitigate the possible unintended consequences of using force, including complicating the military campaign against the Islamic State. All this will require something in which the administration has shown little interest: smart diplomacy.
That smart diplomacy starts with Russia. The administration reportedly previewed the strike with Moscow. Cynics might conclude the fix is in: The United States quietly warns the Russians, they give Mr. Assad a heads-up and tell him not to react, and everyone calls it a day. More likely, the administration wanted to make sure Moscow knew exactly what we were doing so that Moscow would not overreact or leave its forces in harm’s way.
The administration should make clear to Moscow that it will hold it accountable for Mr. Assad’s actions going forward, rally others to do the same and launch more strikes if necessary. The United States should also condition counter-terrorism cooperation with Russia — something Moscow wants — on Russia’s efforts to rein in the Assad regime and push it toward genuine peace negotiations with rebels. Secretary of State Rex Tillerson’s trip to Moscow next week will be pivotal in advancing this message and managing any risk of escalation with Russia.
The administration should play on the likelihood that Russian President Vladimir V. Putin is livid with Mr. Assad. Mr. Putin has helped the dictator gain the upper hand in Syria’s civil war. But Mr. Assad’s renewed use of sarin gas — which the United States and Russia stopped him from employing in 2013 by diplomatically enforcing President Obama’s much maligned red line against chemical weapons — was totally unnecessary and hugely embarrassing to Moscow.
The Russians also know they run an increased risk of blowback for their continued support of Mr. Assad and complicity in his inhumane brutality against Syria’s Sunni community. Syria’s Sunni Arab neighbors and Turkey may now feel compelled to double down on their support for the Syrian opposition, making Moscow’s life a lot harder. Sunni Muslims in Russia, central Asia and the Caucasus will be further enraged against Moscow, and some of the thousands of Chechen fighters in Syria could now seek vengeance back home. The recent horrific attack in the St. Petersburg subway — apparently by an ethnic Uzbek possibly radicalized by the war in Syria — may be a preview of things to come if Moscow does not begin to extricate itself from the Syrian morass. The Trump administration should help Mr. Putin find an exit ramp.
Mr. Trump must also carefully guard against the possible downsides of his actions, especially with regard to the counter-ISIS campaign.
The administration will have to convince Moscow not to complicate life for American pilots by painting them with their potent air defenses, or engaging in dangerous fly-bys. He will have to warn Mr. Assad’s other major patron, Iran, not to retaliate by unleashing its militia in Iraq against American troops. He will have to balance further action against the Assad regime with the need to keep our resources focused on defeating the Islamic State.
And the president will have to control for mission creep. If Mr. Assad persists in the use of chemical or biological weapons, it will take extraordinary discipline to avoid falling into an escalation trap that leads from justified punitive strikes to a broader, and riskier, United States intervention. After all, American involvement in Libya, which I advocated, began as an effort to protect civilians from violence by the government of Col. Muammar el-Qaddafi. But it ended in regime change. Owning Syria would be exponentially more challenging than our already fraught responsibility for post-Qaddafi Libya.
Here at home, Mr. Trump must speak directly to the American people about the country’s mission and its objectives, thoroughly brief Congress and seek its support, and make clear the legal basis for United States actions. And while he’s at it, he should reopen the door he has tried to slam shut on Syrian refugees. The president’s human reaction to the suffering of those gassed by the Assad regime should extend to all the victims of Syria’s civil war, including those fleeing its violence.
Antony J. Blinken, a deputy secretary of state in the Obama administration, is a contributing opinion writer.