Can the U.S. Attack Syria Without its British Ally?

Politicians on both sides of the Atlantic, starting with Winston Churchill, have long spoken about the “special relationship” that exists between the United States and Britain when it comes to international affairs. They’ve been side by side in World War I, World War II, the Korean War, the Cold War, the Gulf War, and the invasions of Iraq and Afghanistan.

But Thursday’s rejection by the British House of Commons of Prime Minister David Cameron’s plea that the British join with the Americans in punishing Syria for its alleged use of chemical weapons leaves the U.S.—at least at this moment—without its most steadfast ally.

Can the U.S. attack Syria without the Brits standing shoulder-to-shoulder with the Americans? Of course, it can. But more importantly, should it?

British politicians made clear they felt the U.S. had dragged them into the war in Iraq a decade ago under false pretenses, and they are in no rush for a reprise. “We are determined to learn the lessons from Iraq,” Labour Party leader Ed Miliband said. “Evidence should precede decision, not decision precede evidence.”

Former senior U.S. military officers think the British vote should stay the President’s trigger finger. “Not having the Brits join any military strike by the U.S. on Syria could be a potential deal-breaker for the entire operation,” says David Barno, a retired Army lieutenant general who commanded allied forces in Afghanistan in 2003-2005. “Having our closest long-term ally opt-out of the mission would make selling this idea here at home and around the world immeasurably harder for the President.”

Not only that, says Robert Scales, a retired Army major general and historian, it would show Obama to be less diplomatically adept than his predecessor: “This would mean that Bush has trumped Obama in collecting a consensus of the willing.”

Administration officials made it clear that the U.S. is consider hammering together an ad hoc alliance—perhaps including France and Turkey—without British participation. “If any action would be taken against Syria,” Defense Secretary Chuck Hagel said Thursday in Brunei, “it would be an international collaboration”—without naming any nations. There is a chance Britain could still back a strike if its Parliament finds the UN inspectors’ report into the Aug. 21 chemical attack compelling, although fingering the guilty party isn’t part of its charter.

The broader the alliance, the more global and moral justification such a retaliatory strike has. If Britain remains on the sidelines, critics will seize on its absence to question the merit, and legitimacy, of any military action.

The British no-vote is the latest brake on the push for a strike that earlier in the week appeared imminent. The Obama Administration has given up trying to win UN approval for an attack, in light of Russian opposition. But it’s important to recall that the U.S. led attacks in the Balkans and Libya without the UN’s blessing.

As another Tomahawk-laden destroyer, USS Stout, joins four U.S. warships already in the eastern Mediterranean, the Administration seemed more interested in the departure of the UN inspectors from Syria. They’re slated to leave Saturday, a day ahead before their agreed-upon departure date with Damascus. That could open the window for an attack, which would likely close late Tuesday, Washington time, when Obama leaves for a trip to Sweden and Russia.

The President looks increasingly like an infantryman walking the point—out in front of the allies, the Congress and the public. The stronger and more compelling the evidence, the easier it is to be out front. But over the course of this week, the Administration has pared away at the evidence it will need to convince the allies and others that war is warranted.

There are apparently no direct links between Assad and last week’s chemical-weapons attack in a Damascus suburb that killed hundreds, sparking this latest crisis. Can there be smoking missiles without a smoking gun?

The Obama Administration maintains it makes no difference whether Assad was “the one that pushes the button or says ‘go,’ on this,” State Department spokeswoman Marie Harf said Wednesday. “The commander in chief of any military is ultimately responsible for decisions made under their leadership.”

Of course, she was speaking of Assad. But she could just have easily been speaking of Obama.