Concord, New Hampshire (CNN) - New Hampshire was no vacation for Rob Portman who made his most public pitch yet to be chosen as Mitt Romney's running mate.
The Ohio senator, rumored to become number two on the GOP ticket, was Romney's chief defender Saturday when he encouraged conservatives to refute President Barack Obama's primary line of attack on Bain Capital by embracing Romney’s career there.
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"I know a lot of smart people in the Obama campaign. I'm sure they've thought through this. But for them to keep talking about the fact that he has private sector experience," Portman said. "You know that's what I think people are looking for is someone who actually knows how to get this economy turned around."
Portman's comments come on the heels of a week of blistering criticism from conservatives and prominent Republicans who called for the Romney campaign to aggressively respond to tactics of Obama's reelection team that includes negative ads about Bain Capital's business methods.
Romney was wrapping up vacation an hour away on Lake Winnipesaukee when Portman broke away from touring colleges with his daughter to explain how the Democrat's strongest defense could backfire.
"In terms of Bain Capital, Mitt Romney's got a proud record. He's a guy who actually was in the business of creating jobs, not just talking about it. And he understands what it means to have a government watchman that can create the environment for job growth, versus one that creates a disincentive for entrepreneurs,"
Portman said, comparing Romney to Obama.
He did not hesitate to address the potential challenges Romney faces in the battleground state of Ohio, where Portman serves as Romney's state chairman.
"We've got our work cut out for us," he said.
"So we've got a lot of catching up to do in Ohio because we had a primary and they didn't, and because they had a lot of resources early on and we didn't. We're starting to develop more of a grassroots infrastructure in Ohio."
Portman cited Romney’s fund-raising prowess, raising more than his Democratic counterparts and disputed criticism from his party that Romney was not effectively challenging his Democratic opponent.
“So we've got huge differences here and I think Mitt Romney's been very aggressive at laying out those differences. He'll have to continue to, because this will be a hard-fought campaign. There will be a lot of back and forth, and people need to look carefully at the facts as they're hearing all these debates back and forth."
Portman said he will meet with former President George H.W. Bush on Sunday. On Monday, he will attend several events in Boston to raise money on behalf of Romney and the Republican Party's Victory Fund.
Portland would not reveal whether he was meeting with Romney aides, particularly his vice presidential vetting team, but did acknowledge he did not plan to meet with Romney during his New England visit.
The senator spent time with Romney when the GOP candidate brought his five-state bus tour to Portman's critical battleground state in mid-June.