Calling Clinton "my friend," McCain heaped praise on the former first lady, suggesting "pundits" and "Democratic "Party elders" unfairly crowned Obama the Democratic nominee.
"The media often overlooked how compassionately she spoke to the concerns and dreams of millions of Americans, and she deserves a lot more appreciation than she sometimes received," McCain said. "As the father of three daughters, I owe her a debt for inspiring millions of women to believe there is no opportunity in this great country beyond their reach."
As the last day of a grueling, five-month Democratic primary battle fight came to a close, Clinton watched as superdelegates flocked to her opponent and told fellow New York lawmakers that she is open to being Obama's vice presidential candidate if he asks.
A year ago, the former first lady led every Democratic presidential candidate in the polls and was considered the party front-runner with big-money Democratic donors, the support of the Democratic establishment, and the backing of her husband, former President Bill Clinton.
But today, Clinton, trailing Obama in delegates, and with her campaign deeply in debt, spent much of the afternoon calling major donors and supporters from her home in Chappaqua, N.Y., in a last-ditch effort to gauge her support.
With only 31 pledged delegates at stake in Tuesday's final primary contests in Montana and South Dakota, the Obama campaign pressed uncommitted superdelegates Tuesday to announce their support before the polls closed, to allow him to emerge as the party's nominee without the appearance of it all coming down to the superdelegates.
He saw an avalanche of superdelegates come his way in the last two days before the final primary contests, including former President Jimmy Carter, and renowned civil-rights leader and House Majority Whip Rep. James Clyburn, D-S.D.
Of the 796 Democratic superdelegates -- party officials, members of Congress and state party leaders free to back any candidate -- less than 200 were still waiting to declare their support for either candidate when the day began.
"We've known for the last couple of months that even though Obama emerged as the front-runner, he was not going to be able to secure the nomination without the support of superdelegates," said Nathan Gonzales, political editor of the Rothenberg Political Report.
Clinton faced pressure to drop out of the race, but refused to leave until the last primary states voted.
This afternoon, Democratic Majority Leader Harry Reid of Nevada, told reporters that he encouraged uncommitted superdelegates in the Senate to hold off on endorsing immediately and to wait for the results of tonight's primaries.
"Sen. Clinton needs to be left alone to get through the primary process and let it run its course," Reid said.
While their phones have been burning up for months with calls from the candidates and former President Bill Clinton, many superdelegates were uncomfortable with their roles as potential kingmakers.
"For senators, you've got a race here between two of their colleagues, and at least one of them is coming back to the Senate, so I think their reluctance to pick a side is to maintain good relations," said Jennifer Duffy of the Cook Political Report.
Clyburn, on Tuesday, urged fellow superdelegates to get off the fence.