Pakistan's Supreme Court said Tuesday it will soon begin examining an expired amnesty covering the president and key allies. The decision launches a process that could unseat the U.S.-allied leader just as the Obama administration needs stability in Islamabad to help crack down on the Taliban.
Highlighting the dangers, a suicide bomber killed an anti-Taliban lawmaker in the Swat Valley _ the latest in a series of bombings as the army presses offensives in militant strongholds close to the Afghan border.
President Asif Ali Zardari has been under mounting pressure to resign or relinquish key powers to the prime minister and assume a ceremonial role.
Those calls came to the fore with Saturday's expiration of an amnesty that had been granted to him and more than 8,000 other politicians and bureaucrats under his predecessor.
A statement issued Tuesday said the Supreme Court has received petitions calling the amnesty a violation of fundamental rights. It said the court has notified all concerned parties that it will start proceedings on the cases Monday.
The amnesty was part of a deal with then-President Pervez Musharraf that paved the way for former Prime Minister Benazir Bhutto to return from self-exile and take part in politics without facing cases her party says were politically motivated. Zardari took control of the party after Bhutto, his wife, died in a suicide bombing Dec. 27, 2007.
The amnesty expired on Saturday, opening the possibility that opponents could petition the court to challenge his eligibility for office. Zardari generally enjoys immunity from prosecution but legal experts have said that could be revoked if the amnesty were determined to be illegal.
His office declined to comment on the Supreme Court decision.
The legal process is likely to take months and is far from certain to deliver a fatal blow to Zardari's presidency, but the speed with which the court announced its intention to hear petitions suggests it wants to move ahead forcefully.
Earlier this year, Zardari gave in to street protests and reinstated Iftikhar Mohammed Chaudhry as chief justice after he was fired by Musharraf. Many analysts took Zardari's reluctance to reinstate Chaudhry as a sign he feared the justice would try to undermine his rule.
Zardari, 54, has long been haunted by corruption allegations dating to governments led by Bhutto, and spent several years in prison. He denies any wrongdoing.
The opposition also has called on Zardari to give up sweeping powers he inherited from Musharraf.
Pakistan's original constitution envisaged a parliamentary style of government, in which a popularly elected prime minister is the chief executive and the president is a ceremonial head of state. But Musharraf, who was widely despised when he left office, accumulated powers to stay in charge.
Zardari relinquished command of Pakistan's nuclear arsenal on Friday and has said he would give up more powers in the near future.
The domestic woes have threatened to distract the administration as it battles Taliban and al-Qaida militants on the border.
President Barack Obama telephoned Zardari on Tuesday night to outline his new Afghan strategy.
"President Barack Obama mentioned the broad outlines of the U.S. Afghan policy," Zardari's office said in a statement. "President Obama reaffirmed U.S. commitment to a long-term partnership with Pakistan for security and stability."
Washington's strategy calls for an expanded partnership with Pakistan in return for increased efforts to root out extremists in the border area while the U.S. sends thousands more troops to Afghanistan.
Islamabad has expressed fears that a surge in American troops could drive more extremists into Pakistan.
The suicide bomber blew himself up among guests greeting provincial assembly member Shamsher Khan in his house near the main Swat Valley town of Mingora, police and hospital officials said. Nine other people were wounded, including the lawmaker's brother.
Khan, 59, was a member of the secular Awami National Party and a supporter of army offensives against militants in the region, as well as education for girls.
Regional police chief Idrees Khan said the bomber's head was severed from his body and he appeared to be about 16 years old.
Swat Valley was the site of a military offensive this summer that was largely considered a success. But sporadic bombings and clashes still occur, raising fears many militants escaped and could regroup.
Similar concerns have been expressed about an army assault that began in October in the border region of South Waziristan.
Associated Press writers Asif Shahzad in Islamabad and Riaz Khan in Peshawar contributed to this report.