CINCINNATI (AP) — Ohio Sen. Rob Portman will be in Colorado on Wednesday to offer counterpoints during President Barack Obama's campaign visit there, and he will accompany Mitt Romney on a three-city Ohio trip next week that concludes with a rally in his home region of southern Ohio.

The Romney campaign said Tuesday that details of the Aug. 14 bus tour in Ohio will be announced later, but a campaign website promoted an evening rally next Tuesday outside the Ross County Courthouse in Chillicothe that would wrap up Romney's four-state bus trip.

Portman launched his political career with a 1993 special election victory in House District 2. The district stretches east from suburban Cincinnati, where he lives, into Appalachian Ohio and now includes Chillicothe after being redrawn for Ohio's congressional reapportionment because the state lost two seats after the 2010 Census.

Details also will be announced later on Portman's trip Wednesday to Colorado for the Romney campaign. The president is scheduled to be in four Colorado cities over two days beginning Wednesday. Like Ohio, Colorado is a highly contested state.

Portman, believed to be among the top contenders for Romney's running mate pick, has campaigned for the presumptive GOP presidential nominee in other battleground states, including North Carolina and Pennsylvania. The Romney campaign has said his decision on a running mate could come any day, but it has said little else about the search. At least two other possible contenders, Florida Sen. Marco Rubio and Virginia Gov. Bob McDonnell, are expected to join Romney on the bus tour when it is in their home states.

Portman's office said he will be in central Ohio this weekend to take part in the Pelotonia bicycle ride to benefit cancer research.

Portman's top credentials for the Republican national ticket are generally considered to be his deep experience in Congress and from Cabinet-level roles as U.S. trade representative and White House budget director. The first-term senator's home state is also traditionally crucial to GOP White House hopes.

Democrats are highlighting Portman's ties to former President George W. Bush, who left office unpopular and amid a national financial crisis. And some Republicans say Romney should make a bolder choice than Portman.

Not Diane Carnes, chairwoman of the Ross County Republican Party.

"That is absolutely what I want it to be," she said of Portman on the ticket. She predicted a big turnout Tuesday evening for the Romney visit with him.

"The place will be jumping," she said.

John McCain outpolled Obama in the southern region of Ohio while losing the state in 2008, but Democrats such as Bill Clinton have carried the area in presidential elections. The Obama re-election campaign has had an office in Chillicothe for months.

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