ABU DHABI, United Arab Emirates -- Defense Secretary Robert M. Gates acknowledged yesterday that the Bush administration underestimated the difficulty of getting a political truce in Iraq, where the government of Prime Minister Nouri al-Maliki has been crippled by a walkout of Sunni Muslim ministers.
Gates insisted that he was optimistic about military progress in several Iraqi regions, particularly western Anbar province, once a haven for insurgents.
But he said he was discouraged by the inability of Iraq's Shiite-led government to reach a compromise on legislation aimed at reconciling the country's ethnic and sectarian groups. Reaching such political agreements, a central goal of the troop buildup in Iraq, may still be far off, he said.
"I just think in some ways we probably all underestimated the depth of the mistrust and how difficult it would be for these guys to come together," Gates said.
Gates' remarks were his closest yet to conceding that the Bush administration's top political priorities for Iraq might not occur during the troop buildup, even if it extended into next spring, the latest the military could sustain the increase. He is the top administration official to express such skepticism publicly.
Gates made the remarks to reporters on his plane after a three-day, four-country visit to urge Sunni Arab allies to do more to support al-Maliki's government.
Since the beginning of the troop buildup in February, Gates has been circumspect in his assessment of the strategy's progress and has been careful not to wade into the political fight between the White House and Capitol Hill over the duration of the increase.
Although Gates testified on Capitol Hill that he would like to see the buildup end by December, a senior defense official familiar with his thinking said those views had "been overtaken by events." Gates, the official said, is awaiting next month's evaluation from Gen. David Petraeus, the top U.S. military commander in Iraq, to decide how long to continue the current security plan.
In Baghdad yesterday, al-Maliki's Shiite Muslim party urged Iraq's main Sunni Arab bloc to reconsider its decision to quit the Cabinet. Al-Maliki had not accepted the resignations yesterday, said Sami Askari, an aide to the prime minister and member of his Islamic Dawa Party.
Al-Maliki's party said it was worried that the Sunni bloc quit the Cabinet "before exhausting all means of dialogue."
"The current situation in Iraq and the continued terrorist operations targeting innocent civilians and infrastructure demands national solidarity," the party said in a statement.
U.S. officials had hoped the inclusion of Sunni Arabs in al-Maliki's Cabinet would give them a stake in Iraq's political process and undercut support for the insurgency. But a year later, Sunni politicians complain that they have nothing to show for their participation.
"The issue cannot be resolved with appeals alone," said Iyad Samarrai, secretary-general of the Iraqi Islamic Party, a leading member of the Accordance Front, a Sunni coalition. "The basis of the problem must be resolved."
In Washington yesterday, House Democrats passed a measure to require more rest at home for troops serving in Iraq, taking another swipe at President Bush's management of the war on the eve of Congress' summer recess.
The legislation - which passed 229-194, with six Republicans joining virtually all of the chamber's Democrats to support it - stands little chance of becoming law.
A similar proposal sponsored by Democratic Sen. Jim Webb of Virginia was blocked by Senate Republicans last month. And the White House issued a veto threat yesterday against the House bill.
The House proposal would prevent the redeployment of active-duty troops to Iraq until they had been stationed at home for the same period of time they served in the war zone.
The proposal would require three times as much rest at home for members of the Reserves and National Guard.
In Iraq, much of Baghdad was without running water yesterday and had been for at least 24 hours, compounding the urban misery in a war zone and the blistering heat at the height of the Baghdad summer, the Associated Press reported.
Residents and city officials said large sections in the west of the capital had been virtually dry for six days because the already strained electricity grid cannot provide sufficient power to run water purification and pumping stations.
Baghdad routinely suffers from periodic water outages, but this one is described by residents as one of the most extended and widespread in recent memory.
At least 28 Iraqis were reported killed yesterday by bomb blasts, mortar fire and other violence. In the worst of the incidents, a suicide bomber drove his explosives-laden car into a crowd of recruits at a police station northeast of the capital, killing at least 13 people and injuring 15, police said.
Police in Baghdad also recovered at least 24 unidentified bodies, many of them apparent victims of sectarian killing in the city's western neighborhoods.
Peter Spiegel and Alexandra Zavis write for the Los Angeles Times.