Pakistani Party Quits Cabinet Over Justices

But diplomatic sources here said there was frustration among Pakistan's Western allies that the civilian leadership had failed to resolve the judicial issue at a time of pressing national problems.

Leaders of the People's Party took pains to say they would continue to work with others to prevent any systemic breakdown. Sherry Rehman, federal information minister, said Monday that there was no danger of a government collapse and that her party would not retaliate against Sharif by walking out of the politically powerful Punjab provincial government.

"Our aim is to soften the fallout from all this," Rehman said in an interview. "We regret that they are leaving the coalition, but we will continue our working relationship. We can't afford a constitutional crisis."

The rift between Zardari and Sharif leaves unresolved a second, more significant power struggle between Musharraf and the former chief justice, Iftikhar Mohammed Chaudhry. Chaudhry, an iconoclastic figure, challenged Musharraf in a society where judges have traditionally deferred to the military. Musharraf tried to fire him twice and declared a state of emergency last November while the high court was preparing to rule on the legality of his presidency.

Although Musharraf doffed his uniform in December and had been seen as wielding less power in recent months, Monday's political breakdown could give him more room to reassert himself as a power broker, analysts said. As a civilian president, he has the authority to dissolve Parliament and appoint military commanders.

Ultimately, the greatest threat to Pakistan's political evolution is the possibility of military intervention. So far, the new army chief has shown no interest in politics. But if renewed protests should erupt over the judicial dispute, food and fuel prices should continue to rise, or civilian authorities should fail to address the rising threat of violent extremism, some fear the army could be tempted to take over, as it has done before.

"At the end of the day, what's at stake here is the civil-military balance," said Babar Sattar, a lawyer and columnist who has written extensively about the judicial issue. "Does the army have an intervention streak, or does it step in because nothing else works? This infighting between politicians, so soon after eight years of military dictatorship, is a very big mistake."

Staff writer Robin Wright in Washington contributed to this report.