BAGHDAD — After a day of sleeping, praying and even swimming in the Green Zone, the government citadel historically off limits to ordinary Iraqis, protesters began leaving Sunday evening on orders from the man who had sent them: Moktada al-Sadr, the influential Shiite cleric.

In a statement issued from the holy city of Najaf in southern Iraq, Mr. Sadr directed his followers to leave the Green Zone in an orderly fashion, to chant for Iraq and not a sect, and to help clean the space they had occupied.

A day earlier, hundreds of protesters demanding an end to corruption stormed the fortified Green Zone in dramatic scenes that hinted at revolution. But by Sunday evening the episode had become something less: an affirmation of Mr. Sadr’s sway over the street, but one aimed at pressuring the government to enact promised reforms rather than bringing it down.

The question in the days ahead is whether Prime Minister Haider al-Abadi, who is Shiite, and the rest of Iraq’s ruling elite can come together to form a new cabinet of capable ministers, and not loyalists to a party or sect, something that Mr. Sadr has demanded and Mr. Abadi has promised.