UNITED NATIONS — President Mahmoud Abbas, the Palestinian leader, formally requested full United Nations membership for his as yet undefined country on Friday.  But before the thunderous applause greeting his announcement in the General Assembly had faded, international powers laid out a new plan to resume direct Israeli-Palestinian peace talks that was designed to delay a contentious vote on the Palestinian request as long as possible. 

In a day full of diplomatic theater, Mr. Abbas and Prime Minister Benjamin Netanyahu of Israel each laid out the tangled history of their bloody conflict in passionate, lengthy speeches less than an hour apart, while the United States, Russia and European powers haggled in a back room for a formula to bring the parties back to the negotiating table and prevent the Palestinian bid for membership from becoming a spur for violence. 

Continents away, thousands of Palestinians celebrated around the West Bank, with cheers erupting from the rapt crowds watching live when Mr. Abbas held aloft the four pages of the United Nations application letter — a symbolic step toward international recognition of statehood that many Palestinians also saw as a form of peaceful defiance against Israel.