Former President Bill Clinton, underscoring his wife's determination against statistically long odds of overcoming Obama's pledged delegate lead, said in California Sunday a "vigorous debate" was good for the party and those who want to see the former first lady quit the contest should just "chill out."
"We're going to win this election if we just chill out and let everybody have their say," Clinton said.
A crowd of about 20,000 was chilled as supporters waited in cool temperatures for Obama to speak on the campus lawn at Penn State University, where the Illinois senator agreed that the tough campaign was healthy if frustrating.
"As this primary has gone on a little bit long, there have been people who've been voicing some frustration," Obama said.
"I want everybody to understand that this has been a great contest, great for America. It's engaged and involved people like never before. I think it's terrific that Senator Clinton's supporters have been as passionate as my supporters have been because that makes the people invested and engaged in this process, and I am absolutely confident that when this primary season is over Democrats will be united."
After Vermont Sen. Patrick Leahy last week became the first leading Democrat to openly call on Clinton to abandon her bid and back Obama, the front-runner said Clinton should stay in the race as long as she wanted. He also said he had not talked to Leahy before he issued his statement on Clinton leaving the race. But Leahy's sentiment is shared by many activists worried that a drawn-out nominating contest only bolsters Republican nominee-in-waiting.
Other Obama supporters have echoed that view while stopping short of asking Clinton to withdraw.
New Mexico Gov. Bill Richardson on Sunday called Obama's lead all but insurmountable, while Massachusetts Sen. John Kerry said the contest would be reaching "a point of judgment" very soon.
"I don't think it's up to our campaign or any individual to tell Hillary Clinton or their campaign when that is," Kerry, the 2004 Democratic nominee, said on ABC's "This Week" on Sunday. "But there will be, I think, a consensus about it, and I think it's going to occur over these next weeks."
Obama picked up the endorsement of Minnesota Sen. Amy Klobuchar Sunday night, giving him another superdelegate supporter.
In a statement provided to The Associated Press, Klobuchar said Obama "has inspired an enthusiasm and idealism that we have not seen in this country in a long time."
In a statement, Obama said he's grateful for Klobuchar's support. According to the Obama campaign, Klobuchar is the 64th superdelegate to endorse him since the Feb. 5th Super Tuesday contests.
Last week, Obama picked up the support of Sen. Bob Casey Jr., D-Pa., giving the candidate a boost heading into the Pennsylvania primary on April 22.
Richardson, D-N.M., who chose "loyalty to the nation" over his long-standing ties to the Clintons in backing Obama, toldthat while superdelegates should play a key role, the party "big-shots" should not ultimately determine the party's nominee. "It should the voters."
As she has fought through three-months of primary voting, Clinton has been able count on a deep well of support from women voters, many of whom see the attempt to push her out of the race now as the work of a male-dominated party structure.
In California, Clinton beat Obama by a margin of 59 percent to 36 percent among women. She bettered him by 54 percent to 45 percent among women in Ohio, an important general election battleground state.
Obama, in turn, has walloped Clinton among men in nearly every state. He has prevailed among women in just a handful of places, including his home state of Illinois and states with large black populations.
As Obama crossed Pennsylvania, which votes on April 22, he pounded his message of reform and said again that McCain was running for U.S. President George W. Bush's third term.
McCain, the Arizona senator and Vietnam war hero, gave a major foreign policy speech last week trying to blunt Democratic attempts to paint him as a candidate who would view the world through Bush's pre-emptive foreign policy lens.
"Our great power does not mean we can do whatever we want whenever we want, nor should we assume we have all the wisdom and knowledge necessary to succeed," said in the carefully honed speech to the Los Angeles World Affairs Council. "We need to listen to the views and respect the collective will of our democratic allies."
Nevertheless, McCain has not backed away from his support for the unpopular Iraq war and has, in fact, said his candidacy would likely stand or fall on the outcome. Violence has flared anew in Iraq despite the U.S. troop surge that McCain said has been a success.
CBSNews.com senior political editor Vaughn Ververs reports that McCain has launched a new tour to reintroduce himself to the American electorate, but he's running his campaign in a way that seeks to separate him from the many woes facing the GOP.
"John McCain, it appears, is going to be a party of one," says Ververs in an.
Clinton, in vowing to continue her campaign until August if necessary, returned to the open Democratic Party sore of the negated primary votes in Michigan and Florida.
She won both contests, but the national party had said in advance the contests would not count because the state parties ignored the prohibition against holding the votes too early. Obama had taken his name off the Michigan ballot for that reason and neither candidate focused campaigning in those states.
But Clinton trails Obama by 1,624 to 1,499 in national delegates, including both those pledged as a result of state primaries and caucuses as well as superdelegates - elected and party officials who can vote for whomever they wish.
Clinton now insists the Michigan and Florida votes be added to her tally. She won in both states.