Washington ? President Bush will hold an Oval Office meeting with a key Iraqi Shiite leader today amid a scramble to bolster the strife-torn nation’s unity government before it collapses in civil war.

The meeting with Abdul Aziz al-Hakim, leader of the Supreme Council for the Islamic Revolution, is considered an effort to boost support for Iraqi Prime Minister Nouri al-Maliki, with whom Bush met in Jordan last Thursday. Al-Hakim is a leading opponent of anti-U.S. Shiite Muslim cleric Muqtada al-Sadr, who controls the most powerful bloc in Iraq’s ruling coalition.

The administration hopes that by urging Hakim and other al-Sadr rivals to support Maliki more forcefully, they can reign in the growing radical influence of al-Sadr and his Mahdi Army militia, two senior administration officials said Sunday.

Bush’s meeting with Hakim, two days before a bipartisan Iraq Study Group issues its recommendations for a new U.S. approach to Iraq, comes in the wake of news leaks reflecting a far more pessimistic outlook about the war among Bush’s top advisers than the administration has expressed publicly. In the latest leaked memo, Defense Secretary Donald Rumsfeld wrote two days before his Nov. 8 resignation that the U.S. strategy was “not working well enough or fast enough” and that “a major adjustment” was needed, the New York Times and Washington Post reported.

On NBC’s “Meet the Press” Sunday, National Security Adviser Stephen Hadley dismissed Rumsfeld’s memo as “a laundry list of ideas” that was submitted in response to Bush’s request to a number of agencies for new approaches.

Hadley said the president is reviewing his Iraq policy and that the study group’s report will be “an important input,” but that Bush also wants to hear from Congress, his military commanders and Iraqi leaders before making any policy decisions.

While conceding administration mistakes in Iraq, Hadley insisted that the United States has “not failed” in the war. He warned that a pullout of U.S. troops would create “a safe haven” for al-Qaida.

The two senior officials, who insisted upon anonymity because their remarks were not cleared by the White House, said the administration has seized on the central proposal in a leaked, Nov. 8 Hadley memo to Bush that urged an end to Maliki’s reliance on al-Sadr.