WASHINGTON — To celebrate his 30th birthday, U.S. Rep. Patrick Murphy of Florida threw himself a campaign fundraiser. Then another. And another. And another.The four events this spring helped make Murphy, a Democrat from Jupiter, one of the House's top fundraisers, and he can't let up.Scraping out victory in the country's most expensive and vicious House race of 2012, and ending the career of tea party hero Allen West in the process, Murphy faces another high-profile campaign that will test the delicate line he walks in a quintessential swing district.It will also answer the burning question of whether voters like what they see in the young Democrat, who is trying to cultivate a bipartisan voting record, or if they had simply seen enough of the bombastic West."It's a microcosm of House Democrats' dilemma," said David Wasserman, an elections expert with the nonpartisan Cook Political Report. "While the national Republican brand is historically abysmal, Democrats have more raw, vulnerable seats to defend, and Murphy's is a prime example."Another one of those seats is south of Murphy in Miami, where fellow freshman Rep. Joe Garcia will have a tough battle. Democrats, meanwhile, think they have a good chance at regaining a seat in the Panhandle, where two-term Rep. Steve Southerland is likely to face Gwen Graham, daughter of former Gov. Bob Graham.Nationally, Democrats seem unlikely to erase the GOP's 33-seat advantage in the House. Midterm elections have been historically unkind to the party that controls the White House and tend to draw older, white voters who vote Republican.In a bitter twist, the loss of a polarizing, donation-attracting opponent may make it harder for Murphy, one of just nine Democrats in the country to win a district that went for Mitt Romney over Barack Obama. "His prospects of winning a second term are almost entirely dependent on Republicans nominating someone who is unpalatable to independent voters," said Wasserman, who gives Murphy no more than a 35 percent chance of besting any generic Republican.The GOP began targeting Murphy immediately after he won the District 18 seat, which touches Palm Beach, St. Lucie and Martin counties, confident their voter registration advantage will benefit a less controversial candidate. Republicans make up about 38 percent of the electorate; Democrats, 36 percent; independents, 26 percent.Most districts in the country are far more one-sided, the result of gerrymandering. It has pushed Democrats to the left and Republicans to the right, resulting in a Congress that rarely cooperates. "I'm lucky I'm in a seat where I can be myself," said Murphy, a Republican until 2011.His early fundraising success, pulling in more than $550,000 in the first quarter, has not scared off competitors. Three Republicans have entered the race already and at least that many are considering."It's all out of my control. We have to do our job here," Murphy said, projecting a nonchalance that belies his aggressive fundraising. He just went through one of the roughest campaigns in America and faces another one, but Murphy seems to be going out of his way to be bland.Sitting in a sparsely decorated office across from the Capitol, a press assistant by his side, he offered flat lines about keeping his head down, focusing on local concerns like beach renourishment, and sloughed off a question about balancing elected duties with the intense pressures of nonstop fundraising. Asked about West, he said: "I certainly don't spend much time thinking about him. My focus is on my job."That same day Murphy fired off an email warning donors about a political action committee West recently created, asserting it would soon be flooded with tea party money. "After last year, we know that we are going to be his number one target."West, now a Fox News contributor who hasn't said if he'll run in 2014, declined comment. He can raise money, having pulled in more than $19 million compared with Murphy's $4.7 million in 2012. Outside groups spent another $6.5 million for and against Murphy, making it the costliest race in America.And the nastiest. Murphy painted his opponent as a loudmouth bully. A super PAC ad funded by Murphy's father, a Miami developer, depicted West, who is black, punching white women. West made an ad out of an incident when Murphy was 19 and arrested in Miami on charges of disorderly intoxication. Voting was so close that it took two weeks for West to concede defeat. Vice President Joe Biden showed up at a swearing-in party for Murphy and told the crowd, "You did the country a favor."Murphy has tried to live up to the moderate image he campaigned on, joining a group of freshmen in search of bipartisan solutions to the national debt and other issues. In May, he appeared in West Palm Beach with Republican Rep. David Joyce of Ohio, promoting a bill that would cut a modest $200 billion from the budget through efficiencies.Murphy has broken with his party several times. He sided with Republicans on a measure requiring the president to produce a budget that balanced within 10 years, was one of just 19 Democrats to vote for the Keystone XL pipeline and recently backed a farm bill extension that most Democrats objected to because it would have forced new work requirements for food stamp recipients.Republicans say they were safe votes to take and point out that Murphy mostly votes with his party, including against efforts to repeal Obamacare. He voted for Nancy Pelosi for House speaker, as did all but seven Democrats."For all that he talks about reaching across the aisle, and all the local press he gets for it, when it counts, he doesn't," said Sid Dinerstein, former head of the GOP in Palm Beach County. Murphy, he said, will certainly face a more "mainstream" Republican this go-around.Murphy said he is confident he has enough moderate Republican support. "I think a lot of them are very upset with their party, whether it's gun issues, immigration, a woman's right to choose."If Murphy needs validation he was making the right moves he might look to Tony Fransetta, a Democratic activist in Wellington."Some of his votes may not be exactly what we want, but he replaced a resident nut who would try to grab headlines by going for the extremes," he said. "Patrick Murphy is a little bit conservative but stands a great chance of being re-elected."