A lightning-quick offensive has seen Syria’s opposition take control of major cities and large swaths of territory, toppling the government of longtime leader President Bashar al-Assad and indelibly altering the war-torn country’s future.

The events represent a remarkable reversal of fortunes in Syria and enlivened a multipronged civil war that appeared largely stagnant for years. The situation, analysts told Al Jazeera, also appears to have been largely unanticipated by the administration of United States President Joe Biden, and raises galling questions over how Washington will proceed in the weeks and months ahead.