Six weeks ago, President Bush paid a surprise visit to Iraq’s prime minister, Nuri Kamal al-Maliki, in Baghdad. American forces had just killed the terrorist leader Abu Musab al-Zarqawi. Iraq’s Parliament had just confirmed new ministers to run the army and the police, completing what was billed as a national unity cabinet. Mr. Maliki seized the occasion to announce a major military operation meant to bring security to the people of Baghdad. Mr. Bush took one of his patented looks into the prime minister’s eyes and found a worthy partner.

This week, as Mr. Maliki returns the visit, things feel very different. It seems possible, in fact, that the two men’s brief encounter in Baghdad might turn out to have been the last good moment of the American experience in Iraq.

Despite the elimination of Mr. Zarqawi and the new security drive, the daily carnage is increasing, especially in Baghdad and especially against civilians. Last month, for the first time, the nationwide civilian death toll exceeded 100 people per day. Despite the increased presence of Sunni Arabs in the new cabinet, the political and physical gulf between Sunnis and Shiites is wider then ever; the flight of frightened families from religiously mixed neighborhoods is further cleaving the country in two.

And despite Mr. Maliki’s assurances that sectarian armies would be disarmed and their members integrated into the ranks of the national army and the police, Shiite militias like the Mahdi Army and the Badr Brigades continue to rule the streets and kill Sunnis with impunity.