U.S. Sen. Scott Brown swept into office riding a wave of frustration with President Barack Obama's push for a health care overhaul and his handling of a faltering economy _ a win that was also a banner victory for a nascent tea party. Now, as he gears up for a re-election campaign, the Massachusetts Republican is busily casting himself as a bipartisan bridge builder in a bitterly divided Congress.

Democrats have been quick to portray Brown as beholden to Washington Republicans, however, while also calling a recent remark he made about Democratic front-runner Elizabeth Warren demeaning to women.

In the past week, Brown has decried political divisiveness on the Senate floor, sent a letter to Senate Majority Leader Harry Reid and Republican Senate Minority Leader Mitch McConnell echoing the same sentiments, and urged Reid in a phone call to craft a bipartisan version of Barack Obama's jobs bill.

For Massachusetts voters who are far more likely to elect Democrats, Brown's message is simple.

"I'm one of the most bipartisan, if not the most bipartisan, senator there and I'm going to continue to do what I've been doing to be that independent voter and thinker," Brown told reporters after hosting a recent jobs fair in Boston.

Brown's campaign message hit a snag last week, however, following a Democratic primary debate in which Warren quipped that she kept her "clothes on" when asked how she paid for college. The questioner had mentioned Brown's decision to pose nude for Cosmopolitan magazine as a law student.

Brown shot back during a radio interview two days later, laughing and saying "Thank God" when asked about Warren's comment.

Democrats immediately criticized Brown's remark as sexist, but Brown later said he was just responding to a "wisecrack" from Warren about a decision he made to pay for school.

"She was joking, I was joking and I'm not quite sure what else to say," he said.

On Sunday, House Democratic Leader Nancy Pelosi weighed in, saying Brown's remark about Warren, a Harvard professor and consumer advocate, shows he's clueless about women.

"I thought it spoke volumes about how clueless Sen. Brown is," the California Democrat said Sunday on ABC's "This Week." "It really spoke volumes about, really, disrespect for women he may not even realize."

The change from tea party firebrand to bipartisan dealmaker has been an evolution for Brown, who won a 2010 special election for the seat left vacant by the death of longtime Democratic Sen. Edward Kennedy by vowing to be the "the 41st senator that could stop the Obama" health care law.

Now, Brown says he's a Republican who supports key elements of Obama's jobs bill, including an extension of the payroll tax cut. Brown said he also supports an expansion of tax credits for businesses that hire unemployed members of the military and a repeal or delay of a withholding tax on government contractors.

Brown said he urged Reid in a phone call last week "to move on a bill that we can all agree on."

"Take everything out of that (jobs) bill that we agree on and pass it right away in a bipartisan, bicameral manner because you want to put forth a bill that is actually going to pass," Brown said he told Reid.

It's a message Brown echoed on the floor of the Senate days earlier.

"How can any member here in the Senate vote 100 percent of the time with their own party?" Brown said. "Do they honestly believe that their party is right 100 percent of the time?"

Brown said thornier issues like tax hikes and entitlement reform can be left to the 12-member supercommittee charged with tackling the nation's fiscal problems.

Not everyone has been thrilled at Brown's moderate stance. Some of the same tea party activists who supported him in 2010 say they feel betrayed by some of Brown's votes and won't back him in 2012

Among those votes was Brown's decision to join with fellow Republican Sens. Olympia Snowe Susan Collins of Maine and support a Democrat-backed overhaul of the nation's financial system. Brown's support of a repeal of the military's "don't ask, don't tell" ban on gays serving openly also drew criticism.

Yet Brown hopes those kinds of votes will help him reach out to key independent and Democratic voters, and not all tea party activists are abandoning him.

Christen Varley, president of the Greater Boston Tea Party, hasn't agreed with all of Brown's votes, but she's already written his campaign a check and plans to hold a sign for him on Election Day.

"On the other side of the argument is that we can't afford to lose a Senate seat," Varley said. "It really is a no-brainer. Who's going to run against him?"

Varley said the choice will be all that much clearer if Warren wins her party's primary.

"Her ideology is as far off from us as you can get," Varley said.

Even as he shifts toward the center, Brown's campaign is trying to cast Warren as out of touch with ordinary Americans.

In one recent fundraising email, Brown's campaign manager, Jim Barnett, said Warren was engaging in class warfare with the help of "her ultra-liberal friends" while being "cheered on left-wing blogs."

Barnett's e-mail included a link to a YouTube video of Elizabeth Warren in which she argues "there is nobody in this country who got rich on their own" and that those who do well should take some of their profits and "pay forward for the next kid who comes along."

Warren, who reported raising $3.15 million during the past three months, is one of five Democrats vying for the seat. Brown has $10.5 million in his campaign account.

Democrats are working equally feverishly to tie Brown to what they see as increasingly unpopular GOP in Congress.

"It's clear that Scott Brown is quickly building a record of voting with D.C. Republicans against jobs," Massachusetts Democratic Party Chairman John Walsh said in a recent statement.