ISLAMABAD The rout of his allies in Pakistan's parliamentary election could herald the end for President Pervez Musharraf, one of Washington's most important Muslim allies in its fight against al Qaeda, analysts say.
The United States on Tuesday welcomed the vote as "a step toward the full restoration of democracy" but urged the next government in the nuclear-armed Asian country to work with Musharraf, who seized power in a 1999 military coup.
A wave of sympathy helped the Pakistan People's Party (PPP) of assassinated former Prime Minister Benazir Bhutto to emerge as the largest party in the National Assembly.
But the PPP needs coalition partners and the president's camp is banking on persuading it to invite the pro-Musharraf Pakistan Muslim League (PML) to salvage his leadership.
Bhutto's widower Asif Ali Zardari, who took over as PPP leader after she was killed in December, appeared to take that lifeline away by saying his party would not invite anyone from the PML into the broad-based coalition it planned to form.
The PPP wants Nawaz Sharif, the prime minister Musharraf overthrew in 1999, to join the coalition along with an ethnic Pashtun party that kicked Islamist parties out of power in the North West Frontier Province where militants operate.
Sharif, whose party ran a close second in Monday's poll, has made driving Musharraf from power his mission since returning from exile in Saudi Arabia in November, a month after Bhutto.
Intense negotiations are widely expected over the coming days, and Zardari and Sharif are due to meet on Thursday. If they do not reach agreement, the PPP's door could re-open to Musharraf's supporters.
But Sharif joining forces with the PPP would leave Musharraf with two choices that would mean his demise, said analysts.
They said Musharraf could either quit of his own volition or drag out political upheavals with a hostile parliament that would try to oust him on grounds he violated the constitution by imposing emergency rule last November for a few weeks.
"He has the graceful option and the confrontational option," said Ijaz Shafi Gilani, chairman of pollsters Gallup Pakistan.
In Washington, U.S. State Department spokesman Tom Casey said: "We certainly would hope that whoever becomes prime minister and whoever winds up in charge of the new government would be able to work with (Musharraf)."
On board U.S. President George W. Bush's Air Force One on a flight to Ghana, White House spokeswoman Dana Perino told reporters: "We hope that they continue to work with us as partners in counter-terrorism.
"The threat from extremists is just as grave and very immediate for the people of Pakistan as evidenced by the violence there recently."
Musharraf has relied on three sources of support -- the army, Washington and politicians who deserted old party leaders.
But on top of the PML's election battering, Musharraf quit as army chief last November and U.S. support has been stretched thin due to what many of his critics saw as his autocratic behavior over the past year.
The critics say the army's morale has been damaged by Musharraf's efforts to stay in power despite deep unpopularity.
Political paralysis has played havoc with management of the economy in the last six months, and Pakistanis have had to struggle with soaring fuel prices, shortages of basic foodstuffs and gas, and worsening power cuts.
But investors have appeared impervious to the problems. The Karachi stock market gained three percent on Tuesday, registering relief the vote had passed off with less violence and less rigging than feared.
(Editing by Ralph Gowling)
(To read more about the Pakistan election double click on; and visit the Reuters blog "Pakistan: Now or Never?" at blogs.reuters.com/pakistan/)