THIS MAY BE remembered as the week in which the illusion that the bloodshed in Syria could be stopped by United Nations diplomats was destroyed once and for all. Inside the country, the killing sharply and sickeningly accelerated. In Washington, U.N. envoy Kofi Annan finally had to acknowledge that his calamitous peace initiative, which has provided the United States and its allies with an excuse for inaction for the past 11 weeks, “may be dead.”

Mr. Annan’s concession was forced in part by the latest massacre by a government-backed militia. In a village near Hama, some 80 people were butchered and their homes burned. A BBC reporter who visited the scene tweeted: “You can see that a terrible crime has taken place.” Like a massacre two weeks ago in another village, this was an instance of sectarian cleansing. The militia members came from the Alawite sect of Bashar al-Assad, while the victims were Sunni.

Even Mr. Annan has had to recognize the result of his initiative, which counted on voluntary compliance by Mr. Assad with steps that would doom his regime. “If things do not change, the future is likely to be one of brutal repression, massacres, sectarian violence and even all-out civil war,” Mr. Annan told the United Nations on Thursday. The envoy at last hinted that “pressure” and “consequences” for the Assad regime were called for.

But Mr. Annan is mainly pushing a diplomatic initiative that is even more far-fetched: a “contact group” to settle on a plan for Syria that would include the permanent Security Council members as well as Saudi Arabia, Turkey . . . and Iran. Since Tehran is Mr. Assad’s closest ally, its inclusion would ensure either a solution that favored his regime or a deadlock. No wonder the Russian government, Mr. Assad’s other sponsor, has endorsed the idea and proposed a meeting in Moscow.

The Obama administration continues to oppose measures that might head off the looming catastrophe, such as the creation of protected zones for the Syrian opposition. But it is at least resisting Mr. Annan’s bad idea. Even before meeting him, Secretary of State Hillary Rodham Clinton rejected the idea of including Iran in a contact group.

Ms. Clinton also laid out some specific and worthy parameters for a transition in Syria in a meeting Thursday with the Friends of Syria group in Istanbul. Ms. Clinton and a State Department briefer said these include Mr. Assad’s “full transfer of power” and departure from Syria; a “representative and inclusive interim government” that leads to “free and fair elections”; and “civilian control of the military and security forces.” It’s hard to imagine Iran accepting those terms; for Russia, they would ­install a political model in Damascus that Vladi­mir Putin is fighting to prevent in Moscow.

The administration must now face how it can realistically achieve those aims. As we’ve said before, there’s a lot the United States could do, well short of invasion but well beyond the rhetoric-and-resolution approach it’s taken for more than a year. In Istanbul, Ms. Clinton discussed greater coordination of international aid for the Syrian opposition and a tightening of economic sanctions. These are steps in the right direction; but the transition in Syria will begin only when Mr. Assad is confronted with irresistible force.