THE OBAMA administration has consistently placed excessive faith in Iraqi Prime Minister Nouri al-Maliki, who is scheduled to meet the president at the White House Friday. Ignoring warnings that he harbored a sectarian and authoritarian agenda, U.S. officials supported his formation of a new government after elections in 2010. That’s largely because President Obama and his aides were narrowly focused on the goal of smoothly withdrawing all U.S. troops from Iraq by the end of 2011; the future of the fragile Iraqi political order, established at enormous cost in U.S. lives and resources, came second.

The withdrawal was completed as scheduled, but in the last year Iraq has plunged anew into sectarian warfare. Al-Qaeda, largely defeated by U.S. and Iraqi forces in 2007-08, has strongly resurged and more than 7,000 people have been killed so far this year, according to the United Nations. The new warfare has been triggered in part by the civil war in Syria. But Mr. Maliki also bears responsibility for the breakdown: By persecuting the Sunni and Kurdish communities and undermining institutions such as the parliament and courts, he has done much to polarize his country.

Now, visiting Washington for the first time in two years, Mr. Maliki is pleading for stepped-up U.S. security assistance — and again the Obama administration appears inclined to overlook his toxic behavior. While acknowledging that Iraq’s political problems need to be addressed, the administration is, as The Post’s Anne Gearan reported, quietly supporting Mr. Maliki’s bid to win congressional approval for a sale of Apache attack helicopters and increased sharing of surveillance and other intelligence.

Administration officials, like Mr. Maliki, argue that the aid is in the United States’ interest because of the growing threat posed by al-Qaeda on both sides of the Iraqi-Syrian border. That menace must be addressed, not just in Iraq but also in Syria, where Mr. Obama has doubled down on a policy of passivity. But supplying Mr. Maliki with more air power might make the trouble worse. Helicopters have an ugly history in Iraq: They were used by Saddam Hussein to slaughter civilians. Mr. Maliki already dispatched security forces to attack a Sunni protest encampment this year. How can Iraqis be sure more air power will not be used against Sunni civilians rather than al-Qaeda targets?

Such confidence could come only if additional U.S. aid to the Maliki government is preceded by a major change of political direction. The Iraqi leader must fulfill his frequent promises to reach accords with Sunni and Kurdish leaders on such matters as the country’s internal borders and the sharing of oil revenues. He also must ensure that elections scheduled for next year will be free and fair.

As it is, Mr. Maliki appears to hope that his meeting with Mr. Obama and a pledge of more aid will help propel him to another term in office. He doesn’t deserve such an endorsement.