"My attitude is Senator Clinton can run as long as she wants," Obama said.

Obama told reporters he did not agree with one of his supporters, Vermont Sen. Patrick Leahy, when he said earlier this week that Clinton cannot win the nomination and should therefore drop out. "I hadn't talked to Pat about it," Obama said.

At stops throughout the day, Clinton raised the question of whether she should leave the race _ eliciting loud jeers from supporters.

"There are some people who say we should just stop these elections. 'Enough people have already voted, what's a few million more?'" Clinton said in Louisville, Ky. "I don't know about you but I'm glad Kentucky is going to be voting and you'll be choosing because it's such an important election." The state holds its primary May 20.

Campaigning in Pennsylvania, her husband, Bill Clinton, said party insiders looking to resolve the contest should step back and allow the process to move forward.

"We just need to relax and let this happen. Nobody's talking about wrecking the party," the former president said. "Everywhere I go, all these working people say: 'Don't you dare let her drop out. Don't listen to those people in Washington, they don't represent us.'"

The campaign on Saturday released a fundraising e-mail, signed by Bill Clinton, asking supporters to challenge talk of his wife departing the race by sending a check to her campaign.

"There's no better way to tell Hillary that you support her staying in than to make a contribution to her campaign," he wrote.

Obama offered a bit of tough love to Pennsylvania voters, saying some industrial and manufacturing jobs may not return to this steel region, but others could take their place.

Clinton also stressed job creation at campaign stops in Indiana and Kentucky, vowing to help manufacturers transition to new industries like clean energy and ending tax breaks for American companies that ship jobs overseas.

"I think this election, particularly here in Indiana, is about jobs, jobs, jobs, jobs, jobs, jobs," the former first lady said.

Jobs and the economy are front and center in the remaining primary contests between the two Democratic hopefuls. Pennsylvania, which holds its primary April 22, has seen its manufacturing base and especially its steel industry weakened in recent decades, as has Indiana, which votes May 6.

While campaigning in Ohio, another big manufacturing state, both Clinton and Obama criticized free trade deals and insisted the other candidate was not as reliable a protector of U.S. jobs. Clinton won that state's March 4 primary.

In Johnstown, a woman employed at a call center told Obama that 200 of her co-workers had lost jobs after the work was outsourced to India. She blamed free trade and asked what the Illinois senator would do about it.

"I don't want to make a promise that I can bring back every job that's left Johnstown. It's just not true. Some of those jobs aren't going to come back," Obama answered.

"What I can do is try ... to create an environment in which jobs are being created," he said, adding that they "may not be the same jobs that left and don't come back."

Speaking in Indianapolis, Clinton tied many of the region's economic woes to U.S. trade policy and to President Bush's laissez-faire approach to China, where numerous America jobs have been shipped in recent years.

"We are now deeply in debt. We owe money to everybody, not just to China but to Mexico and practically any other country you can think of. We are $9 trillion in debt," she said.

Obama, who is on a six-day bus tour through Pennsylvania, toured a factory that makes the wires that eventually become Slinky toys. He played with a Slinky through the visit.

Asked whether voters might be turned off by talk of some jobs not coming back, Obama said he was trying to give the phone worker a clear answer.

"The point I was making is that the same jobs are probably not going to come back. We're not going to suddenly see Bethlehem Steel reopen," he said. "What we're going to see is potentially some specialty steel of the sort that we saw at Johnstown Wire that has created a niche that can grow."

Also Saturday, former Democratic contender John Edwards made his first public comments on the race since dropping out two months ago.

"I have a very high opinion of both of them," Edwards said of Obama and Clinton at the Young Democrats of North Carolina convention. "We would be blessed as a nation to have either one of them as president."

At the same event, Chelsea Clinton said her travels have opened her eyes to sexism.

"I didn't really get how much sexism there still was in our country until I was at a rally with my mom in New Hampshire, and someone came up to me and said, 'I just can't see a woman being commander in chief,'" the former first daughter said.

She has always been supported by both the men and women in her family, she said. "I have been so profoundly more grateful than I have ever been over the past few months for my parents because of that."