THE OBSERVERS dispatched by the U.N. Security Council to monitor an illusory “cease fire” in Syria have been reduced to adding up the bodies of massacred civilians. In Houla, a collection of impoverished villages near the city of Homs, they counted 108 after a rampage Friday by a government-backed militia. The dead included 34 women and 49 children.

Fewer than 20 in Houla died from shelling by government tanks and artillery, a U.N. spokesman said Tuesday. The rest were shot at close range and frequently mutilated, their throats cut and their eyes poked out. “Entire families were shot in their houses,” the Associated Press quoted the spokesman, Rupert Colville, as saying.

Horrific as it was, the Houla massacre is not unique, just better documented than the crimes perpetrated by the regime of Bashar al-Assad in towns and cities across Syria. More than 1,000 people have died since the Security Council, with the enthusiastic support of the Obama administration, charged envoy Kofi Annan with implementing a six-point peace plan in late March.

Mr. Annan’s mission has become one of the most costly diplomatic failures in U.N. history. It has allowed the Syrian regime to go on slaughtering civilians and pushed the country down the path to a full-scale sectarian war. But Mr. Annan persists: On Tuesday, he met Mr. Assad in Damascus to renew feckless appeals for steps that the dictator will never take.

The Obama administration persists, too, in declining to exercise the U.S. leadership that would be required to stop the massacres. For the past two months it hid behind Mr. Annan. Now that his plan has become an embarrassment, it is floating a new idea: a Syrian political transition modeled after that of Yemen, where a strongman was pressured into stepping down. The “Yemensky variant” is called that because the key to the new White House figment is none other than Vladi­mir Putin — the Russian strongman who has been struggling to squelch pro-democracy protesters in his own country.

According to a report in Sunday’s New York Times, President Obama hopes to persuade Mr. Putin in a meeting next month that Russia should press Mr. Assad to step down, leaving in power a successor who could negotiate a democratic transition with the opposition.

The odds that Mr. Putin will make this happen are little better than those for Mr. Annan. It’s not likely that the Russian leader wants democracy in Syria, which would lead to the empowerment of leaders disinclined to maintain the current regime’s alliances. Even if Mr. Putin could be persuaded, he probably lacks the means to force out Mr. Assad and his clan. Mr. Obama’s apparent faith that Mr. Putin is ready to do business with him is at odds with the strongman’s recent behavior — including his abrupt cancellation of a planned visit to Camp David.

The reality is that the killing in Syria will continue, and the threat to vital U.S. interests across the Middle East will grow, until Mr. Obama stops counting on the likes of Kofi Annan and Vladi­mir Putin to spare him from the responsibility that should be shouldered by a U.S. president. The longer he waits, the greater the cost — in children’s lives, among other things.