Hillary Clinton has dismissed any notion of pulling out of the race for the Democratic Party's nomination while, for the first time, directly tackling her opponent, Barack Obama, for his past ties with the Chicago pastor Jeremiah Wright.
Mrs Clinton's refusal to stand aside will deepen anxiety among party elders that the nomination slug-fest, which seems to get nastier with each passing day, will only give the advantage to the Republican nominee, John McCain, at the general election in November.
"I think we have to wait and see what happens in the next three months," Mrs Clinton said in Pennsylvania, which holds its primary on 22 April. Polls show she is likely to win but her chances of closing the gap on Mr Obama remain slim.
One senior party figure, Phil Bredesen, the Governor of Tennessee, floated a plan to assemble all the party's super-delegates in June, after the last primary has been held, to cast votes on who should be the nominee. His idea is to avoid a continuation of the in-fighting until the Democratic convention in Denver in late August. "They have a much steeper, rockier hill to climb if it goes all the way to the convention," he said.
"What's been going on for the last 90 days just gets worse and worse as the summer goes on."
Mrs Clinton's credibility suffered a blow this week after her descriptions of landing in Bosnia in 1996 under threat of sniper fire were exposed as overstated. Defending herself as only "human" in having a defective memory, she also tried to switch attention to the Rev Jeremiah Wright. "He would not have been my pastor," she said. "We don't have a choice when it comes to our relatives. We have a choice when it comes to our pastors."
Mr Wright has cancelled guest preacher appearances this week in Florida and Texas. It has emerged that Mr Obama has given $27,500 to his church over the past six years.
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