The bus tour will include Romney appearances with Portman, as well as two others talked about as possible contenders: Virginia Gov. Bob McDonnell and Florida Sen. Marco Rubio.
The tour starts Saturday and will take Romney through four must-win states in as many days: North Carolina, Virginia, Florida and Ohio. All are battlegrounds where Obama won in 2008. And while the president could afford to lose in one or more of them and still reach the 270 electoral votes needed for another term, Romney almost certainly needs all four to beat him.
In first-up Virginia, Romney will stop in Norfolk, the center of the Hampton Roads region. Heavy on military voters, it's a section of the state Republicans have to win if they hope to carry Virginia in November. He'll also visit Ashland and Manassas, northern Virginia cities where his proposal to cut 10 percent of the federal workforce could hurt him.
In North Carolina on Sunday, Romney is hitting both the GOP heartland and the Democratic-heavy research triangle in the Raleigh area. In Florida, he's looking for swing voters in the Orlando area and stopping in Miami to make an appeal to the Cuban-Americans who typically vote Republican.
And in Ohio, he's visiting cities where the white working class vote will make a difference — including areas where Hillary Rodham Clinton was favored over candidate Obama in the 2008 Democratic presidential primary.
The tour is certain to generate both local and national media coverage, giving Romney an opportunity to take his message directly to voters and test out criticisms of Obama for use in the homestretch.
Romney has varied his attacks this week, rolling out ads accusing Obama of waging a "war on religion," pushing to "gut welfare reform" and trying to "use the tragedy of a woman's death for political gain." That last was a reference to an outside group's advertisement that features a man whose wife died of cancer after he lost his health insurance when he was laid off from a company that was bought by the private equity firm Romney once ran.
As August ends, Romney will get perhaps his final chance to make a strong impression with the nation before the homestretch.
Large swaths of the country will get their first close look at the former Massachusetts governor when he accepts his party's nomination in Tampa, Fla., at the party's national convention, an event aimed at providing a week of positive news coverage for the candidate.
The campaign, working with the party, has crafted a program designed to appeal to independents and fire up Romney's conservative base at the same time.
Romney's next big chance to shift momentum in the race — and repair his image — won't come until a series of October debates.
Associated Press Deputy Director of Polling Jennifer Agiesta in Washington and AP Writer Thomas Beaumont in Iowa contributed.
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