William F. Wechsler, director of Middle East programs at the Atlantic Council, a Washington-based research organization, said in an emailed statement that the plan was unlikely to have a major impact in the short term. “The announcement’s chosen timing, specific staging, limited participants, and indeed its substance make clear that it has less to do with a good-faith effort to reach peace between Israelis and Palestinians,” Mr. Wechsler said, “and more to do with the immediate legal and electoral challenges that confront both leaders.”