WASHINGTON -- Cool, calm, personable Rob Portman is the anti-Palin, a top potential Republican vice-presidential candidate who oozes steady wonkishness.

Inside Republican buzz is loud on behalf of the U.S. senator from Ohio who seems to check so many of the boxes that Republican presidential candidate Mitt Romney needs in a running mate. Portman has a resume that includes service in both houses of Congress, two presidential administrations and a big 2010 win in one of the nation’s crucial swing states for the 2012 election.

Perhaps most important, he’s the temperamental and electoral opposite of the last Republican veep hopeful, 2008 nominee Sarah Palin, who was long on charisma but short on depth and experience in national policy.

“He seems like a logical choice for the ticket in so many respects,” said Darrell West, the vice president and director of governance studies at the Brookings Institution, a Washington research group.

The only serious rap on Portman, said Timothy Walch, the author of “At the President’s Side,” a history of the 20th-century vice presidency, is that “he doesn’t bring much sizzle. . . . People might say he’s another guy from the country club.” And some conservatives, as well as Democrats, are ready to pounce on his ties to the Bush administrations.

But those seem small problems, and many conservatives dismiss such concerns. After all, they know him. The 56-year-old son of a forklift-company owner is a veteran Washington insider and Bush family favorite. He was the legislative affairs director in George H.W. Bush’s White House, then a Cincinnati-area congressman for 12 years. He left Congress in 2005 to become President George W. Bush’s U.S. trade representative and eventually served as the director of the White Office of Management and Budget.

“Rob would have strong support,’’ said House Republican Policy Committee Chairman Tom Price of Georgia, who’s a leading congressional conservative.

Portman’s Senate office didn’t respond to requests for comment, and the Romney camp is offering no hints about who or when regarding its choice of a running mate.

Tom Rath, a senior Romney adviser, said Romney was likely to consider “how they fit together, and can he run the country?” as he weighed possible choices. Portman is one of many names on unofficial lists. Also mentioned: former Minnesota Gov. Tim Pawlenty, New Hampshire Sen. Kelly Ayotte, Florida Sen. Marco Rubio and Louisiana Gov. Bobby Jindal. All have campaigned for Romney in swing states recently, trips that also serve as unofficial tryouts.

Portman made several campaign stops in past days in North Carolina, a state that went for President Barack Obama in 2008 and one the Republicans desperately want to win back.

In Winston-Salem, where his wife grew up, Portman attended a fundraising luncheon, and met with business owners and then party activists.

Republicans who attended the fundraiser had heard his name as a possible ticket mate but knew little else about him. Portman, they said, talked like a policy wonk about the intricacies of the federal budget and Romney’s first days in office, explaining each step in plain language and measured tones rather than the incendiary rhetoric of a rally.

At the business session, Portman asked each owner to share thoughts about Washington. He sat in the middle of the roundtable taking detailed notes on index cards and addressed each speaker individually.

Don Frantz, an automotive shop owner and Republican town council member from Cary, N.C., worried about the 2010 health care law’s cost to small business owners. "I was very impressed by his demeanor," Frantz said. "He was one of the first folks to come down from Washington and ask us about our problems and not tell us what our problems are."

The biggest concerns remain Portman’s calm style and, among some conservatives, the Bush administration resume.

“He’s not who we want,” said Judson Phillips, founder of Tea Party Nation, a grass-roots conservative group. “He was front and center, right in the middle of the Bush administration at a time of out-of-control spending.”

Portman probably will have to answer such questions. When Bush nominated Portman as budget director, the president said, “Rob will have a leading role on my economic team. . . . He will be a powerful voice for pro-growth policies and spending restraint.”

Portman was responsible for the fiscal 2008 federal budget. The deficit more than doubled that year, to about $459 billion, as the worst recession since the Great Depression of the 1930s began three months after the fiscal year started.

When Portman sought his Senate seat two years ago, Democrat Lee Fisher tried to paint Portman as an irresponsible spender.

“As Bush’s budget chief,” a Fisher ad charged, “Portman oversaw a spending spree that doubled the deficit.”

Portman won with 57 percent of the vote.