For Hillary Clinton, no 'clear path to victory' -- nor to an exit

Outwardly, Clinton operated Thursday as if the disappointing results from Indiana and North Carolina never happened. She made stops in West Virginia and South Dakota, while her husband held a conference call with top fundraisers. Before dawn, one of her advisors, Mark Penn, crafted a memo outlining future campaign strategy.

But for all the signs of normalcy, much of the infrastructure that keeps the New York senator's campaign going -- the aides, donors and political allies -- is resigned to the hard reality that the Democratic nomination now appears out of reach.

One Clinton aide said Thursday: "There is a profound sadness" among the staff. "I don't think anyone sees that there's a clear path to victory here."

Richard Schiffrin, a national finance co-chairman for Clinton, is scheduled to meet with other fundraisers and her next week. Schiffrin said he would tell her: "Let's look at the situation as it exists and think about whether there's a credible path to the nomination, and if there isn't, what's Plan B?"

He added: "The bottom line is she's going to make a decision that in my view will be in the best interests of the party and the country."

Clinton launched a three-state, 21-hour, cross-country marathon campaign swing Thursday. Speaking to several hundred supporters in the marble-lined dome of the state Capitol in Charleston, W.Va., she acknowledged that she had come under growing pressure to drop out. She suggested that she would stay at least until Tuesday's primary there.

"Some folks say, 'You've got to end this before you get to West Virginia,' " she said. "I think we want to keep this going so the people of West Virginia's voices are heard."

Sen. Barack Obama (D-Ill.) left the campaign trail for a star turn on Capitol Hill, where even Republican lawmakers elbowed past colleagues in the House chamber to shake his hand.

On "NBC Nightly News With Brian Williams," Obama denied that he was the presumptive nominee. "Not yet. I will be," he said, "if Sen. Clinton decides not to go on, or if we complete the six contests and we are ahead as we are now. But nothing is certain. I don't want to take it for granted."