US:AS VOTERS in Montana and South Dakota went to the polls in the final primaries of the Democrats' six-month contest, a stream of superdelegate endorsements put Barack Obama's nomination beyond doubt.
The Associated Press reported last night that Hillary Clinton told a group of New York legislators that she was open to being Mr Obama's vice-presidential running mate.
Mrs Clinton's campaign insisted that she had no plans to concede the nomination last night but she could make a joint appearance with Mr Obama to endorse him as early as today or tomorrow.
Mrs Clinton's campaign chairman, Terry McAuliffe, said yesterday that once Mr Obama gets the majority of convention delegates, "I think Hillary Clinton will congratulate him and call him the nominee."
Other campaign staff urged superdelegates to wait until today before moving behind Mr Obama but assured them that Mrs Clinton would end her campaign later this week if the Illinois senator wins enough delegates.
Former president Jimmy Carter was among the senior party figures who endorsed Mr Obama yesterday, along with House majority whip James Clyburn, the most senior African-American in Congress. "I believe the nomination of Senator Obama is our party's best chance for victory in November, and our nation's best hope for much-needed change. Senator Obama brings a new vision for our future and new voters to our cause. He has created levels of energy and excitement that I have not witnessed since the 1960s," Mr Clyburn said.
"Our party's success going forward will depend in large measure upon how we treat each other between now and our national convention, how we appear to the nation during our national convention, and how we conduct the campaign after our national convention."
Mrs Clinton spent much of the day at her home in Chappaqua, in upstate New York, with her husband, former president Bill Clinton and daughter Chelsea, preparing for an election night event in Manhattan.
Mrs Clinton asked her top donors and senior aides to attend last night's event as her campaign appeared to be winding down.
Advance field staff have been told they are no longer needed and others on the campaign have been asked to submit all outstanding expenses claims by the end of this week.
Mr Clinton has apologised for describing as a "scumbag" the author of an unflattering profile in the magazine Vanity Fair. Mr Clinton said Todd Purdum was "sleazy" and a "dishonest journalist" after he was asked about the article by a reporter who did not identify herself as a journalist.
"President Clinton was understandably upset about an outrageously unfair article, but the language today was inappropriate and he wishes he had not used it," spokesman Jay Carson said.
The article suggested that Mr Clinton's personality has changed since his heart surgery in 2004 and said aides were concerned about the company he is keeping and about alleged liaisons with women.