Two Clinton aides told The Associated Press that for all intents and purposes her campaign is over once Obama clinches the nomination. He could do so Tuesday night, or even sooner, as voters in Montana and South Dakota bring his months-long contest with Clinton to a close and as party superdelegates fall in line behind him.
Clinton aides said the New York senator will acknowledge that Obama has got the necessary delegates once he's over the top, although she planned to stop short of formally suspending or ending her campaign. They spoke on condition of anonymity because they were not authorized to divulge her plans.
Clinton campaign chairman Terry McAuliffe suggested as much earlier in the day, saying that once Obama gets the majority of convention delegates, "I think Hillary Clinton will congratulate him and call him the nominee."
Obama edged closer to the nomination with some choreography by the party's superdelegates. The party insiders were lining up behind Obama at a rate that could seal the nomination once results are in from Montana and South Dakota-or even before.
Two more superdelegates endorsed him Tuesday morning, from Michigan and Missouri, leaving him just 40 delegates short of the 2,118 needed to put him over the top and make him the nation's first black presidential nominee from a major party.
Clinton, once seen as a sure bet in her historic quest to become the first female president, was still pressing the superdelegates to support her fading candidacy. But McAuliffe indicated she was not inclined to drag out a dispute over delegates from the unsanctioned Michigan primary despite feeling shortchanged by a weekend compromise by the party's rules committee that she could still appeal to a higher level.
"I don't think she's going to go to the credentials committee," he said on NBC's "Today" show. Taking the matter to that committee would essentially extend the dispute into the convention and deny Democrats the unity they sorely want to achieve against Republican John McCain.
Seeing the cards fall into place for his November rival, McCain planned a prime time speech Tuesday night in the New Orleans suburb of Kenner, La., in what is essentially a kickoff of the fall campaign.
Obama told The Associated Press on Monday that "we've got a lot of work to do in terms of bringing the party together" with the convention approaching.
"Once the last votes are cast, then it's in everybody's interest to resolve this quickly so we can pivot," he said.
Obama said there were a lot of superdelegates who have been private supporters of his but wanted to respect the process by not endorsing until the final primaries were done.
"We're still working the phones and we're still talking to people ... so we'll certainly have to wait until a little later tonight to see what the final tally is, but we certainly feel good waking up this morning," Robert Gibbs, Obama's spokesman, told CNN on Tuesday.
In a defiant shot across the GOP bow, Obama, who returned to hometown Chicago late Monday, planned to hold his wrap-up rally in St. Paul, Minn., at the arena that will be the site of the Republican National Convention in September.
Clinton returned to New York, the state she represents in the Senate, planning an end-of-primary evening rally in Manhattan after a grueling campaign finale as she pushed through South Dakota on Monday.
"I'm just very grateful we kept this campaign going until South Dakota would have the last word," she said at a restaurant in Rapid City in one of her final campaign stops. Polls suggested Obama would win both South Dakota and Montana.
She still sounded buoyant. Her biggest booster and most tireless campaigner, husband Bill Clinton, didn't. "This may be the last day I'm ever involved in a campaign of this kind," the former president said somberly as he stumped for her in South Dakota.
Ahead of Tuesday's concluding primaries, Obama sought to set the stage for reconciliation, praising Clinton's endurance and determination and offering to meet with her-on her terms-"once the dust settles" from their race.
"The sooner we can bring the party together, the sooner we can start focusing on McCain in November," Obama told reporters in Michigan. He said he spoke with Clinton on Sunday when he called to congratulate her on winning the Puerto Rico primary, most likely her last hurrah.
That fueled speculation for a "dream ticket" in which Clinton would become Obama's running mate-but neither camp was suggesting that was much of a possibility.
In the AP interview, Obama was asked when he would start looking for a running mate.
"The day after I have gotten that last delegate needed to officially claim the nomination, I'll start thinking about vice presidential nominees," he said. "It's a very important decision, and it's one where I'm going to have to take some time."
Clinton finished a whirlwind four days of campaigning that took her from New York to Puerto Rico to South Dakota and back. For a campaign pushing against long odds, it was a show of determination.
The former first lady, suffering from a recurrent cough, had to cede the microphone to her daughter Chelsea twice Monday as she struggled to recover her voice. Chelsea promptly took the opportunity-to discuss health care.
Associated Press writers Kathy Hoffman, Kim Hefling, Beth Fouhy, Nedra Pickler, Jim Kuhnhenn, Stephen Ohlemacher and Jim Davenport contributed to this report.