Susan Davis

USA TODAY

Jolly is a lobbyist and former aide to the late Rep. C.W. %22Bill%22 Young

More than 25%25 of the district is older than 65%2C and as many as half are retirees

Jolly will increase the House GOP majority to 233 in the 435-member chamber

WASHINGTON — Republican David Jolly defeated Democrat Alex Sink in a hotly contested special election Tuesday for the U.S. House with a campaign in which he championed repeal of President Obama's health care law and said Sink would be a vote to advance the president's agenda.

Jolly is a lobbyist and former aide to the late Rep. C.W. "Bill" Young, whose death last October sparked the special election. Jolly was backed by Young's family and while he was outspent two-to-one by Sink's campaign, a flood of nearly $5 million in outside money evened the playing field in a race in which nearly $12 million was spent, including $9 million of outside special interest money.

He narrowly defeated Sink by 3400 votes, 48.4%-46.5%, in a district contained entirely within Pinellas County. While Sink displayed an early advantage with early and mail-in vote tallies, Jolly rebounded with a strong Election Day turnout among GOP voters.

The contest for the St. Petersburg-area district drew national interest and millions in special interest money because the district is a competitive swing seat and an early indicator of how the electorate is leaning — and which campaign messages are working — in this midterm election year.

"David proved that Pinellas County voters are tired of the devastating policies of this administration," said Rep. Greg Walden, R-Ore., who runs the House GOP's campaign committee. Walden said that Sink was "ultimately brought down because of her unwavering support for Obamacare, and that should be a loud warning for other Democrats running coast to coast."

Democrats said that the district's demographic — predominantly older, white voters—played heavily in Jolly's favor. More than 25% of the district is older than 65, and as many as half of the voters were retirees. The swing nature of the seat means Democrats will attempt a pick-up again in November when turnout will be higher, House Democratic campaign chairman Rep. Steve Israel, D-N.Y., said in a statement. Sink has not said if she will make another bid. Israel maintained that the GOP's repeal message is "out of touch" and explained why Jolly's margin of victory was so narrow.

Jolly will increase the House GOP majority to 233 in the 435-member chamber.

Control of the House is not in contention in 2014 according to a broad array of non-partisan election forecasters, but control of the U.S. Senate is in play. Republican candidates across the 2014 battlefield are also running on messages to repeal Obamacare.

Jolly's victory over a better-known candidate in a district won twice by Obama in 2008 and 2012 is likely to fuel Democratic concerns about the impact of not only the health care law but the drag of an unpopular president on Democratic candidates in competitive races.

Contributing: Associated Press