WASHINGTON — Barack Obama was poised to clinch the Democratic presidential nomination — probably Tuesday night, though possibly Wednesday — as rival Hillary Clinton sent strong signals that she's close to ending her White house bid.
As voters in Montana and South Dakota went to the polls Tuesday in the year's final primaries, Democratic superdelegates flocked to Obama's side throughout the day. He picked up 10 delegates who'd been committed to former North Carolina Sen. John Edwards, as well as the backing of South Carolina Rep. James Clyburn, the highest-ranking black official in the House of Representatives, and of House Budget Committee Chairman John Spratt, D-S.C. In all, Obama gained at least 25 endorsements from superdelegates Tuesday, with more poised to announce for him imminently.
The Associated Press declared late Tuesday afternoon that Obama had clinched 2,123 delegates, five more than needed, but it based its count on 22 delegates that it said had confirmed to it privately that they'd endorse Obama later.
Thirty-one delegates were at stake in Tuesday's primaries, and a handful of other superdelegates indicated that they'd announce their endorsements of Obama once the polls closed.
As of early afternoon, Obama aides thought they could meet the 2,118 delegate-majority threshold by the end of the night, but were leaving open the possibility that it would be Wednesday before the senator could make that announcement. The Obama campaign said just before 6 p.m. EDT that it was only 12 short.
Some key uncommitted delegates were urging that Clinton not be pushed out of the race too swiftly.
"Senator Clinton needs to be left alone," said Senate Majority Leader Harry Reid, D-Nev. "Let's get through the process."
But the process appeared to be racing toward its end, and talk surfaced about an Obama-Clinton ticket. It came up when the New York senator spoke to her state's congressional delegation in an afternoon conference call.
"She made it clear ... that she would do whatever it would take to win the election, including being vice president," said Rep. Charles Rangel, D-N.Y., the dean of the state's delegation, who was on the call.
Rangel, who said Clinton wouldn't bring up the vice presidency when speaking publicly Tuesday night, said he'd spoken to her earlier in the day about going on the ticket. He wouldn't reveal details of their conversation, but noted that she and Obama first would have to overcome some hurdles.
"There has to be some discussion to make sure we have one campaign philosophically and politically," Rangel said, adding, "You need to date a little before you get married."
Other superdelegates offered similar cautions.
Sen. Thomas Carper, D-Del., said he'd urged Obama to give his colleague the first right of refusal to be on the ticket, and Sen. Dianne Feinstein, D-Calif., suggested that Clinton would make a good running mate.
Obama wasn't talking publicly about a ticket. His campaign spent Tuesday watching a slow but steady roster of superdelegates — party officials and dignitaries — come his way. At least two dozen committed to him by 5 p.m. EDT Tuesday, with former President Jimmy Carter and a handful of members of Congress expected to add their names once the polls closed Tuesday night.
The biggest remaining bloc of uncommitted superdelegates was on Capitol Hill. In the Senate, 17 members remained uncommitted as of late afternoon Tuesday. Most wanted to wait until Wednesday before deciding whether to endorse anyone right away, though Sen. Max Baucus, D-Mont., said he'd be guided by the results of his state's primary Tuesday.
Other senators said they were wary of backing Obama before they heard from Clinton, a respected colleague they didn't want to hurt.
"For most of us, we probably won't be there — ready for an endorsement — until tomorrow. It's important Senator Clinton be given some space," said Sen. Ken Salazar, D-Colo.
Led by Sen. Tom Harkin, D-Iowa, the uncommitted Senate superdelegates plan to meet on Capitol Hill at 9:30 a.m. Wednesday, about the same time that Clinton and Obama are addressing the American Israel Public Affairs Committee at the nearby Washington Convention Center.
Speculation at the Capitol was that Obama could join the senators quickly for an appearance that would officially put him over the number of delegates needed to clinch the nomination.
But Harkin said that the uncommitted senators weren't sure they wanted to make such a collective statement; that was to be a topic of discussion for Wednesday.
Like others, he said that they didn't want to embarrass Clinton.
"I have enormous regard for her, and she is the first serious woman candidate," explained Sen. Russ Feingold, D-Wis. "In this town, people often think you have to stick it in someone's eye, and that's a mistake. People should relax and let things take their course."
Reid strongly suggested that he'd try to set that course, but he wouldn't give a timetable. "I will set an example for the rest of the Senate," he said.
(William Douglas, Margaret Talev and Lisa Zagaroli contributed to this story.)