ATLANTA — Democratic Rep. John Barrow can thank Mitt Romney voters willing to cross party lines for re-electing him to Congress in a campaign he was supposed to lose.

Barrow of Augusta defied the odds Tuesday when he defeated Republican Lee Anderson in east Georgia's 12th District, which lawmakers redrew last year to give the GOP a big advantage. Regardless, unofficial returns showed Barrow winning a fifth term with 54 percent of the vote.

An analysis of the vote shows Barrow prevailed by reaching beyond voters supportive of President Barack Obama to win over many independents and Republican voters. Barrow got 138,965 votes — giving him more than 19,000 votes than Obama received in the district. Those weren't all necessarily Romney voters. Libertarian Gary Johnson received fewer than 6,500 presidential votes in the district.

Still, Republicans acknowledged Wednesday they were stunned by the bipartisan support for Barrow.

"We took a drubbing. It was a beating," said Wright McLeod, an attorney from Augusta who ran unsuccessfully in the Republican primary for the seat and threw his support behind Anderson. "I look at Congressman Barrow and, though I've never met him, his ability to withstand this district makes him even more formidable in two years."

During the campaign, Anderson and the National Republican Congressional Committee sought to tie Barrow to Obama as if they were running mates. Anderson rarely said Barrow's name without also mentioning the president.

But Barrow, as the seasoned incumbent, had far more money to spend — $2.6 million compared to just over $1 million raised by his Republican opponent. Barrow spent it on TV ads that talked up his vote against Obama's health-care overhaul, touted his endorsement by conservative business groups and that showed him cocking a rifle to remind voters of his support for the National Rifle Association.

"For every ad that was run against him, I think he ran two," said Rick Allen, the Augusta businessman who also sought the GOP nomination to challenge Barrow. "You'd see a negative ad against Barrow from someone, either the NRCC or an outside group. But every time you saw one of those, John came back with an ad like he's saving taxpayers money."

When Republican lawmakers retooled Barrow's district last year to cut out Savannah, the congressman's home and his Democratic base, it was the second time he'd been rendered politically homeless by redistricting. The same thing had happened years earlier when his hometown of Athens was cut from the 12th District. For the 2012 race, Barrow moved to Augusta — his third zip code after eight years in office.

Anderson, a state lawmaker and hay farmer from Grovetown, emerged the winner from a bruising four-way primary for the GOP nomination. His blunt, unpolished style and stumbles in primary debates didn't sit well with some GOP voters. Gwen Fulcher Young, a Republican and wife of former Augusta Mayor Bob Young, unflatteringly compared Anderson to 7-year-old reality TV star Honey Boo Boo. She became one of Barrow's most high-profile GOP supporters.

Anderson's refusal to debate Barrow proved part of his undoing.

"I've run into people who said they're not happy with the fact Lee didn't debate," said Robert Finnegan, Republican Party chairman for Richmond County. "Some people were telling me they'd rather stick with the known than the unknown. They felt that they didn't know Lee that well because they had never seen him debate."

While he openly wooed Republican votes, Barrow also managed to maintain support among Democrats. He hasn't always had an easy relationship in his own party. Barrow outraged many Democrats in the district in 2009 when he voted against Obama's Affordable Care Act. This year, the congressman refused to say outright if he would vote for Obama — though he made it clear he didn't support Romney.

Lowell Greenbaum, chairman of the Richmond County Democratic Party, said he's learned to accept that Barrow's political survival requires "playing Republican in certain places and playing Democrat in others." He cited Barrow's pro-gun ad, which showed him brandishing a revolver and a rifle, as one example.

"He told me before he won that it was extraordinarily popular with the voters and he got a lot of compliments on that," Greenbaum said. "Some of us liberal Democrats ducked when we saw that ad."

Unofficial returns showed Barrow carried just nine of the 19 counties in his district. But he dominated Augusta and surrounding Richmond County, now the district's population center and its Democratic base, where Barrow received a whopping 72 percent of the vote.

Both Allen and McLeod said they may make another attempt at Barrow's seat in two years. Allen is betting the congressman will be more vulnerable in the 2014 midterm elections, but he's not predicting an easy race.

"We've got to have a candidate that can debate, that can do grassroots, that can raise money and articulate a point of view on the issues," Allen said. "If you're going to beat John Barrow, you'd better be good at everything."