Sen. Rob Portman told a New York City audience Monday he was better suited to stay put in the U.S. Senate than be vice president.  Today, he sounded more like Mitt Romney's running mate - using a number of public appearances to promote the presumptive Republican nominee, attack President Obama, and of course, deny that he's interested in the job.

When asked by conservative radio talk show host Laura Ingraham about the Democratic ad attacking Romney on his record at Bain Capital, Portman said Romney simply knows how business works.

"I actually like that portion they used in their ads where Mitt Romney is saying, 'I know how jobs come and how jobs go,'" Portman said. "That's just the reality in a free market system."

Responding to a question about the effectiveness of the ad, Portman pivoted and mentioned Tuesday's CBS/New York Times poll, which shows Romney leading Obama 46 percent to 43 percent - numbers that are within the poll's margin of error. Portman said in the wake of the president's official announcement, the anniversary of Osama bin Laden's death, heavy Democratic ad buys, and a rough Republican primary, a three-point lead bodes very well for Romney.

"At this point before the election in 1980, Ronald Reagan was down about 15 points," Portman said. "I think Mitt Romney goes into the general election in much stronger shape than people thought he would, and frankly it's surprising that he's doing so well."

Portman used a fiscal summit in Washington to continue his attacks on Obama. When asked whether the country's fiscal problems were at least partly to blame on Republicans, Portman pointed to the president's failure to support his own party during super committee negotiations last fall.

"I will tell you, not to be partisan, God forbid… it's about presidential leadership and frankly, it's about providing cover to your own party," Portman told his audience. "I will say that Democrats needed a little help in terms of the super committee and didn't have that. In fact, what we had was a veto threat if it wasn't done just the way President Obama wanted it done and that's not leadership."

The Ohio Republican was so on-message that when asked during his radio interview about his personal response to the president's "evolution" on gay marriage and whether Republicans were "anti-gay," Portman talked about Romney.

"I don't think Mitt Romney is anti-anything. Honestly, it's tough for [the administration] to attack him on his position when it was the position the president had a week or so ago."

It became clear as he was pressed further on his stance on gay marriage that Portman did not want to discuss it further.

"My view on it, and I've talked to you about it before, I don't think this is going to be the key issue in this campaign," Portman said.

Portman reiterated that he wasn't interested in the vice presidency, telling Ingraham, "I'm not interested in leaving where I am. I really don't think that's in the cards for me."

That is, until it is.