TAMPA, Fla. — Republican Sen. Scott Brown, running for re-election in Democratic Massachusetts, came here today and offered a carefully framed endorsement of former Bay State Gov. Mitt Romney, the GOP presidential nominee.

“I’m here because it’s a special day for Massachusetts,” Brown said to a gaggle of reporters in a hotel meeting room not far from the Tampa Bay Times Forum where Romney will officially accept the Republican White House nod. “Whether they be Democrat or Republican, it’s good for Massachusetts when one of our own rises to this level.”

Brown said his presence was “important” because it showed “a pro-choice, moderate Republican” was a part of the GOP’s “big tent.”

“While I don’t agree with everything in the platform and/or with Gov. Romney, I have a lot of respect for him,” Brown said.

Brown faces a tough race against consumer advocate and Harvard Law School professor Elizabeth Warren (D).

Warren recently began airing ads that run against the national Republican brand — and the party’s position on abortion — rather than Brown specifically.

The ads underline the careful path Brown will have to chart if he is to win in a state that will comfortably vote to re-elect President Barack Obama. But the Senator said he didn’t think his appearance here would hurt his standing with voters back in Massachusetts.

“They know where I stand being the second most bipartisan Senator in the United States Senate, voting 54 percent with my party,” he said.

“People in Massachusetts know me,” he said. “I know Professor Warren would like to run a national platform against Gov. Romney and [GOP vice presidential nominee] Paul Ryan, but she’s running against me.”

“I am a moderate, pro-choice Republican who is truly bipartisan,” he said. “You’re not going to get that with her. People know that.”

Roll Call rates the Massachusetts Senate race as a Tossup.

Brown said he had never been to a convention before and didn’t know what to expect.

“You guys probably know more than I, so I’ll ask you where I should go and what should I do,” Brown joked with reporters.

“Pretty much, whatever you want,” one said.

“I want to go to the gym,” the Senator said, chuckling.