Hillary Clinton will remain in Kentucky Monday in preparation for her likely Tuesday primary victory there, while Barack Obama travels from Oregon to Montana, departing from the state where he spent the weekend and is expected to carry in Tuesday's contest.

Speaking in Bowling Green, Ky., on Sunday, Clinton made the case that the primary season should go on until all the states have voted, saying Democrats should not rush to name a nominee. She embraced the fact she was alone campaigning in the Bluegrass State.

"There are some folks, you can see them on TV every night, who wanted it to be over for me after Iowa," Clinton said during a rally on Sunday. "Every time they say it, something funny happens: the voters don’t agree. so what I am hoping is that on Tuesday you’re going to send a real message to a lot of those folks who didn’t want you to vote."

Obama, however, has begun speaking in the past tense regarding the Democratic primary race, saying in one speech that it had been hard fought. At a fund-raiser on Saturday night, Obama predicted the votes he gets Tuesday will "put him over the top" and he will have won the majority of the pledged delegates.

On Sunday, the Illinois senator modified his earlier statement, saying many undecided superdelegates remain, but he repeated that Tuesday could be a major milestone.

"We think we will have a majority of pledged delegates at that point, and that's a pretty significant mark. That means that after contests in every state, or almost every state and the territories that we are we have received the majority of the delegates that are assigned by voters," he told Oregon voters, adding that, "It doesn't mean we've declared victory because I won't be the nominee until we have a combination of both pledged delegates and super delegates to hit the mark."

It takes 2,026 delegates to win the nomination. Obama currently has 1,907 pledged and superdelegates. Clinton has 1,718, but she is not about to give up until the final five races are complete. A Clinton spokesman told FOX News on Sunday, "We'll let the voters in the remaining states make their voices heard."

Kentucky has 51 pledged delegates and nine superdelegates to offer. Oregon has 52 pledged delegates and 13 superdelegates. Clinton leads in Kentucky by an average 30.5 points, according to RealClearPolitics.com. Obama is ahead in Oregon by 12.4 points, the RCP average shows. While Clinton had a healthy 1,200 people show up at one event in Kentucky on Sunday, the Obama campaign said 75,000 turned out to hear him speak at a rally in Portland.Even as the candidates focus on what is happening in the primary states, the big question in Washington is whether Obama should choose Clinton for his running mate.

"That's a judgment he's got to make," Sen. Joe Biden, a former Democratic presidential candidate told ABC's "This Week." "I don't know whether Hillary would want to do that. Look, no matter what happens in this campaign -- let's assume Hillary is not the nominee -- she's still the most powerful woman in American politics."

"This is the poetry and prose coming together. It would be a wonderful solution, and I think all the objections to it -- and I'm eager to hear what they are -- are not strong ones," former New York Gov. Mario Cuomo told CBS' "Face the Nation."

In Oregon on Sunday, Obama focused much attention on the general election, but did not speak about his potential running mate, saying only that to win in November, the Democratic Party has to be unified. To that end, he told supporters, "That means all of you have to be nice to Clinton supporters."

But Obama did speak to his potential next opponent, presumptive Republican nominee John McCain, who Obama claims wants to follow President Bush's idea and privatize part of Social Security."Let me be clear, privatizing Social Security was a bad idea when George W. Bush proposed it, it's a bad idea today," Obama said. "That's why I stood up against this plan in the Senate and that's why I won't stand for it as president."

Bush proposed a Social Security plan in 2005 that focused on creating private accounts for younger workers, but it never came up for a vote in Congress. Democrats strongly opposed the idea and few Republicans embraced it.

Obama said McCain would push to raise the retirement age for collecting Social Security benefits or trim annual cost-of-living increases. Obama has rejected both ideas as solutions to the funding crisis projected for Social Security in favor of making higher-income workers pay more into the system.

"We have to protect Social Security for future generations without pushing the burden onto seniors who have earned the right to retire in dignity," he said.

The McCain camp shot back that Obama wants to raise Social Security taxes. McCain spokesman Tucker Bounds also accused Obama of making "misinformed partisan attacks."

"John McCain has been clear about his belief that we must fix Social Security for future generations and keep our promises to today's retirees, but raising taxes should not be the answer to every problem," Bounds said.

Obama plans to be in Iowa on Tuesday night as election results come in from Oregon and Kentucky. Iowa is a state Obama won four months ago in a caucus win that propelled him to the front of the Democratic pack. It is considered a must-win state for both Republicans and Democrats.

FOX News' Caroline Shively, Molly Henneberg, Aaron Bruns and Bonney Kapp and The Associated Press contributed to this report.