President Hamid Karzai's challenger withdrew Sunday from next weekend's runoff election, effectively handing the incumbent a victory but raising doubts about the credibility of the government at a time when the U.S. is seeking an effective partner in the war against the Taliban.
Former Foreign Minister Abdullah Abdullah said he made his decision after Karzai turned down his demands for changes in the Independent Election Commission and other measures that he said would prevent massive fraud, which marred the first round of balloting Aug. 20.
Abdullah stopped short of calling for an electoral boycott and urged his followers "not to go to the streets, not to demonstrate."
Azizullah Lodin, the head of the Karzai-appointed commission, said he would have to confer with constitutional lawyers before deciding later Sunday whether the runoff would proceed without Abdullah.
Kai Eide, the top U.N. official in Afghanistan, said in a statement that the next step is to "bring this electoral process to a conclusion in a legal and timely manner."
The statement did not address whether the runoff should go forward, though U.N. spokesman Aleem Siddique said it looked impractical.
"It's difficult to see how you can have a runoff with only one candidate," Siddique said.
A clouded electoral picture further complicates the Obama administration's efforts to decide whether to send tens of thousands more troops to Afghanistan to battle the Taliban and its al Qaeda allies.
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The White House has been waiting for a new government in Kabul to announce a decision, but the war has intensified in the meantime. October was the deadliest month of the war for U.S. forces with at least 57 American deaths.
Before the announcement, U.S. Secretary of State Hillary Rodham Clinton downplayed the prospect of an Abdullah withdrawal, saying it would not undermine the legitimacy of the election.
"I don't think it has anything to do with the legitimacy of the election," Clinton told reporters Saturday in Abu Dhabi. "It's a personal choice which may or may not be made."
Nevertheless, the contentious electoral process, marked by massive fraud in the Aug. 20 first round vote, has divided anti-Taliban groups at a time when the U.S. and its allies are pressing for unity in the face of growing insurgent strength.
U.S. officials pressured Karzai into agreeing to a runoff after U.N.-backed auditors threw out nearly a third of his votes from the August ballot, citing fraud.
Karzai's campaign spokesman, Waheed Omar, said it was "very unfortunate" that Abdullah had withdrawn but that the Saturday runoff should proceed.
"We believe that the elections have to go on, the process has to complete itself, the people of Afghanistan have to be given the right to vote," Omar said.
In an emotional speech, Abdullah told supporters that the Karzai-appointed election commission had engineered massive fraud in the first round vote, but his demands for replacing the top leadership had been rejected.
"I will not participate in the Nov. 7 election," Abdullah said, because a "transparent election is not possible."
Abdullah told reporters later that he was not calling for a boycott, but instead leaving it up to his supporters to decide whether to vote if a runoff goes forward on Saturday.
He said he made the decision "with a lot of pain" and hoped his withdrawal would "give the people of Afghanistan a chance to move on."
As recently as Saturday night, Abdullah staffers were saying he would call for supporters to boycott and for the runoff to be delayed until spring with an interim government in place until then. Abdullah said he made his final decision to take a softer stance in consideration of the cost in terms of lives, resources and time and effort.
Abdullah's running mate, Homayoun Assefy, said it was up to the government's Independent Election Commission to decide whether to hold the runoff next Saturday as scheduled.
Abdullah also made no mention of agreeing to take part in any future unity government with Karzai, which the U.S. and its international partners believe is the best hope for curbing the Taliban insurgency.
Instead, Abdullah said Karzai's government had not been legitimate since its mandate expired last May. The Supreme Court, appointed by Karzai, extended his mandate after the election was put off from last spring until August.
"In one hour, all my conditions could have been implemented. Unfortunately, until the last moment we were waiting, but we heard they rejected our appeals," Abdullah said.
He said the people of Afghanistan "have the right" to a free and fair election but the last ballot "was a failure."
Obama administration officials said they would be receptive to a power-sharing deal to avoid a runoff if Karzai and Abdullah could agree on a formula.
But Abdullah decided to exit the race after talks between the two sides broke down Thursday, according to two people close to the negotiations. They spoke on condition of anonymity because they were not authorized to speak for the candidate.
During recent talks, Abdullah demanded the removal of three key election officials, suspension of three Cabinet members and constitutional changes that would give him a say in the appointment of ministers and in major policy decisions, according to an Afghan close to the Karzai campaign.
Karzai refused to agree to the conditions, the Afghan said, speaking on condition of anonymity because he was not supposed to talk about the confidential discussions.
By Associated Press Writers Heidi Vogt and Rahim Faiez; AP Writer Todd Pitman, Amir Shah and Robert H. Reid contributed to this report