As the United States has turned its attention to defeating the Islamic State group, it has softened its stance on the Syrian leader. More than four years ago, Obama demanded that Assad leave power. Administration officials later said Assad did not have to step down on “Day One” of a political transition. Now, they are going further.

A peace plan agreed to last weekend by 17 nations meeting in Vienna says nothing about Assad’s future, but states that “free and fair elections would be held pursuant to the new constitution within 18 months.” To clarify the timeline, the State Department said this past week that the clock starts once Assad’s representatives and opposition figures begin talks on a constitution. The vote would determine a new parliament, though not necessarily a new president.

Getting to constitutional talks will be difficult. It implies that Syria’s warring parties first reach a cease-fire and establish a transition government — something unattainable so far. Neither Syria’s government nor its fractured opposition has endorsed the strategy yet or done much to advance it.

“Nothing can start before defeating the terrorists who occupy parts of Syria,” Assad recently told Italian state television.