US Democratic candidate Hillary Clinton tonight vowed to stay in the White House race, rejecting a fellow senator's suggestion that she pull out to improve their party's chances in November.
"There are millions of reasons to continue this race," New York Senator Clinton told reporters after Vermont Democratic Senator Patrick Leahy, a backer of Clinton rival Barack Obama, said it might be time for her to withdraw.
Many political experts believe Mrs Clinton will have a hard time defeating Mr Obama for the Democratic nomination to run against Republican Senator John McCain in November's election.
Embarking on a six-day bus tour of Pennsylvania, which holds the next primary on April 22nd, Mr Obama said the race for the Democratic nomination was "a good movie that lasted about a half an hour too long." Mrs Clinton pounced on the comment. "I like long movies," she said.
Polls show Mrs Clinton leading by a wide margin in Pennsylvania but Mr Obama picked up a valuable endorsement from popular Pennsylvania Democratic Senator Robert Casey. The endorsement could help Mr Obama with Catholics and blue-collar white voters who may otherwise be attracted to Mrs Clinton.
Mr Casey said the campaign was a chance for change, new politics and healing. "I believe in my heart that there is one person who is uniquely qualified to lead us in that direction and that is Barack Obama," Mr Casey said in Pittsburgh as Mr Obama stood on stage next to him. Many Democrats are worried that the increasingly bitter battle between Mrs Clinton and Mr Obama can only help Mr McCain who has clinched the Republican nomination.
The Arizona senator today aired the first TV ad for the November election. Mr Leahy said in a statement Mr McCain was getting a free ride in the news media "because the Democratic candidates have to focus not on him but on each other." "Senator Clinton has every right, but not a very good reason, to remain a candidate for as long as she wants to," he said.
Mrs Clinton is behind Mr Obama in the race for 2,024 nominating delegates but still thinks she can win and all Democrats should get a chance to vote.