"We'll be back!" demonstrators threatened as they withdrew from the parliament building in the high-security Green Zone on Monday to return to Tahrir Square, in the heart of Baghdad. Every Friday, Iraqis from all social strata have gathered there to protest the government. They began by demanding better water and power provisions, but are now calling for political reforms, a government reshuffling and an effective fight against corruption. The movement was started by artists and then joined by activists. Now it is being led by Muqtada al-Sadr. When the protests were in danger of fading, the influential Shiite cleric called in his supporters and took control of the movement. Fueled by al-Sadr, the situation escalated dramatically at the end of April.

Thousands of demonstrators stormed the heavily guarded government quarter on the western bank of the Tigris and occupied the parliament building for three days. "All power to the people!" was their cry. The throng rushed past razor wire and security blocks, overpowering watchmen and bodyguards. The Green Zone - which houses parliament, the prime minister's government headquarters, the Defense Ministry, and several foreign embassies and nongovernmental organizations - suddenly seemed as porous as Swiss cheese. Security forces refused to fire upon unarmed protesters. Witnesses say that many of the guards were "paralyzed with horror." The situation must have been gratifying for the 42-year-old al-Sadr.

Ten years ago, al-Sadr was a rebel feared by all. He was known to be angry, radical and violent. His supporters roamed the streets of Baghdad, kidnapping and massacring Sunnis, terrorizing entire neighborhoods and helping to speed the city's segregation along religious lines; many such divisions still exist today. The outbreak of the three-year civil war was largely attributed to the Mahdi Army, al-Sadr's private militia, which consisted of nearly 50,000 men. They formed death squads and killed many of those who had been connected to the overthrown government of Saddam Hussein. With such actions, al-Sadr also exacted bloody revenge for the murder of his father, the highly respected Shiite Ayatollah Mohammed Sadiq al-Sadr, at the hands of Saddam's henchmen. The Baghdad neighborhood Saddam City then became known as Sadr City.

'At the gates'

The United States was not spared al-Sadr's wrath. His militiamen claim to have used no less than 6,000 improvised explosive devices in their fight against US forces. When the United States issued an arrest warrant for the "Shiite terrorist," he fled to Iran to engage in religious studies in Qom, his office announced. After US troops left Iraq in 2012, al-Sadr surprised everyone by returning to pray alongside a Sunni imam in Baghdad's Abdul Qadir al-Kilani mosque. The shared worship was intended to symbolize the reconciliation of the two denominations and would be the first in a series of astonishing turns by al-Sadr.

While his supporters had taken up government posts and supported Prime Minister Nuri al-Maliki, al-Sadr suddenly joined Sunni demonstrators in protesting al-Maliki and calling for more rights and political participation in what had become a Shiite-influenced Iraq. He instructed his Mahdi Army to lay down its arms and announced that he would withdraw from politics. With the arrival of "Islamic State," the man with the black turban and graying beard dubbed his Mahdi Army a "Peace Brigade."

Talk of al-Sadr's withdrawal from politics has since passed. Quite the opposite has been the case: At a Baghdad rally on February 26, he publicly criticized al-Maliki's successor, Haider al-Abadi. "The prime minister will have to act as of today," he told the masses gathered at Tahrir Square. Thousands of people had come to hear al-Sadr's message. In the hours before his appearance on an improvised stage, the streets of Baghdad's Karrada neighborhood had been cordoned off and security forces had gathered.

"Today we stand at the gates of the Green Zone," al-Sadr said as he peered out over the Tigris bridge and toward the government district. "Tomorrow we will be inside." Great cheers broke out among the demonstrators: "No to the thieves within, yes to reforms!" Two months later, deeds followed words as crowds stormed the Green Zone.

Iraq still has no government. At a time when the soul of the citizenry is boiling with anger over rampant corruption, the war on terror is robbing the country of its last resources. Oil prices are in free fall and seem to be dragging the economy into the abyss along with them. The time seems ripe for demagogues.

Iraq is struggling to tackle its most pressing problems - fighting Islamic State and unifying the country - with an ineffective political class that is unable to rise above its own internal trench warfare. Muqtada al-Sadr has read the writing on the wall. The question is whether he will use the situation to serve his own ends. "Things don't seem to be in better hands with him," a demonstrator at Tahrir Square said recently. "Clerics instead of politicians? Is that the answer? I fear for my country."