BEIRUT, Lebanon — On the day after his 51st birthday, Bashar al-Assad, the president of Syria, took a victory lap through the dusty streets of a destroyed and empty rebel town that his forces had starved into submission.

Smiling, with his shirt open at the collar, he led officials in dark suits past deserted shops and bombed-out buildings before telling a reporter that — despite a cease-fire announced by the United States and Russia — he was committed “to taking back all areas from the terrorists.” When he says terrorists, he means all who oppose him.

More than five years into the conflict that has shattered his country, displaced half its population and killed hundreds of thousands of people, Mr. Assad denies any responsibility for the destruction.

Instead, he presents himself as a reasonable head of state and the sole unifier who can end the war and reconcile Syria’s people.