WASHINGTON -- With a few exceptions in the past half-century, there has been a simple rule of thumb when it comes to international conflict: America does not use force without Britain at its side.
So when Prime Minister David Cameron was unable to muster the votes in Parliament for support for a strike in Syria -- even one limited to stopping the future use of chemical weapons -- shock could be heard in the voices of senior White House officials who never saw the British rejection coming.
"Bungled by Cameron," said one.
"Embarrassing," said another. "For Cameron, and for us."
Now Mr. Obama is left to cope with miscalculations on both sides of the Atlantic. If he goes ahead with the strike -- which seems all but inevitable, based on the statements of senior administration officials who say the president is determined to restore "international norms" against the use of chemical weapons -- he will look more isolated than any president in recent memory entering a conflict.
True, Britain stayed out of Vietnam -- it was dealing with issues in the Malay Peninsula and Indonesia at the time -- and there was no need for Britain in small actions in Panama and Grenada. Ronald Reagan angered his close partner Margaret Thatcher by providing minimal assistance in the Falklands War. But the Middle East, site of Britain's former empire, is a different matter -- territory in which Britain and the United States have long history and deep interests.
For that reason, it was symbolically important that Britain was side by side with the United States in both Iraq wars in the past two decades, not only marching to Baghdad in 2003 but holding key parts of the country. It was a key player in the Balkans, a NATO operation. And so while its decision to sit this one out, over Mr. Cameron's objections, may have more to do with the specter of Iraq among the British public, it is what one former adviser to Mr. Obama, who declined to be quoted by name, "the kind of setback that reeks of misjudgment and mismanagement."
Other former players in the Obama team, at least when speaking on the record, were only slightly more forgiving. "I think Obama is fighting a lot of war weariness and war wariness in both Britain and the U.S.," said Christopher R. Hill, Mr. Obama's first ambassador to Iraq and a longtime diplomat before becoming dean of the Josef Korbel School of International Studies at the University of Denver. "But you could almost see it coming. When you don't have an overall diplomatic strategy, it's hard to marshal a coalition. It's better to have diplomacy backed by force, than force without a diplomatic strategy."
Instead, Mr. Obama has talked about restoring "international norms" against the use of chemical weapons, an argument he might reasonably believe would resonate with the British public, given the horrific experience British soldiers endured as they faced gas attacks during World War I. He may have also relied on Britain's deep involvement in the Libyan intervention two years ago.
It is unclear when President Obama realized that Mr. Cameron would lose the parliamentary vote. But there is no question that both leaders misjudged the toxic politics of taking military action in the Middle East, even if that action falls short of a true boots-on-the-ground war, as Mr. Obama insisted anew on Friday afternoon that it would. It was curious, for example, that the United States declassified the evidence of chemical weapons use only on Friday afternoon, 24 hours after Parliament had already voted, rather than beforehand, when it could have been put to political use.
But in this case, Mr. Obama has done comparatively little to explain his longer-term strategy for changing the course of events in Syria without getting sucked into a war. In fact, he has argued the opposite -- that a brief strike will do the trick of teaching the Syrians a lesson.
"It doesn't seem credible," said Eliot Cohen, a professor of strategic studies at Johns Hopkins University's School of Advanced International Studies and the author of "Supreme Command," a study of presidents and their relationships with the military. "The argument has been that you can do a strike, call it a day, and say 'We taught them a lesson.'" If so, said Mr. Cohen, who served as a counselor to Secretary of State Condoleezza Rice at the State Department, "I fear it will just be a symbolic use of power."
The British Parliament, however, fears it will be something else: the beginning of another conflict in which the West will inevitably get sucked in.
This article originally appeared in The New York Times.