ROSEBURG, Ore. - As the votes are being counted Tuesday night in Oregon and Kentucky, Sen. Barack Obama plans to hold a triumphant rally in Iowa, returning to the state that propelled him to the top of the Democratic field and sending a clear signal that he has shifted his focus to the general election.

Obama advisers said Iowa was one of several states, along with Missouri, Michigan and Florida, that they had targeted for wins in November and where they plan to campaign even before his primary battle against Sen. Hillary Rodham Clinton ends.

Obama made campaign stops in Missouri and Michigan last week and plans a three-day swing through Florida starting Wednesday.

"John McCain has gone unchallenged for far too long, and we need to start laying out the argument that Barack Obama is the better choice," said Jen Psaki, an Obama spokeswoman, referring to the presumptive Republican nominee.

Obama has tried to draw a series of contrasts with McCain over the past 10 days, giving speeches in Missouri on their economic differences, in Michigan on manufacturing jobs, and in South Dakota on rural and farm issues. During an appearance at a high school in Roseburg yesterday, Obama focused almost exclusively on McCain, telling crowds that a vote for the senator from Arizona would amount to a vote for four more years of President Bush's policies.

"If you agree we've had a great foreign policy over the last four or eight years, then you should vote for John McCain," Obama said. Turning his attention to health care, Obama said that McCain "wants to give you the failed Bush health-care policy for another four years."

McCain's campaign struck back with several e-mails to reporters highlighting what it said were inaccuracies in Obama's attacks. "Whether you're talking about tax increases for hard-working families or a dangerous level of weak judgment, Americans are going to reject a candidate that has no record of bipartisan success," spokesman Tucker Bounds said.

Obama has not forgotten about his battle against Clinton. He is spending the weekend campaigning in Oregon, where he is expected to win Tuesday, and he will spend Monday in Montana, which votes June 3.

But at one point in his speech here, Obama pointedly used past-tense to describe the primary battle with Clinton, saying it "was hard-fought. She was relentless and very effective."

Like Obama, Clinton sought to link McCain to Bush as she started a three-day campaign trip through Kentucky, where she is expected to win Tuesday.

"Sen. McCain's economic policy boils down to this: Don't just continue driving our nation in the wrong direction, put your foot on the accelerator and gun it," Clinton said in Frankfort. "It's hard to imagine, but Sen. McCain and President Bush are like two sides of the same coin, and it doesn't amount to a whole lot of change."

Clinton also directed her attention to "people on TV" who are calling for her to drop out. "All of those people on TV who are telling you and everybody else this race is over and I should just be graceful and say it's over," she said in Loretto, on the grounds of the distillery for Maker's Mark bourbon. "They're not the people who I'm running to be a champion for. I'm running to be a champion for all of you."

Clinton hopes winning the popular vote would convince superdelegates - Democratic party officials and elected officials whose support will determine who wins the race - that she would be the stronger candidate against McCain.

But Clinton has the most overall votes only if the count includes Florida and Michigan, where neither candidate campaigned, and the results were disqualified because the states scheduled primaries in defiance of party rules. Additionally, Obama's name was not on the ballot in Michigan.