Republican Charles Djou took advantage of an intra-party fight among Democrats to snatch a House seat that Democrats had held for 20 years in Hawaii.
Djou, a Honolulu city councilman, won 67,274 votes or 39.5 percent of those cast.
The special election was for the state's 1st congressional district, which opened up after 10-term Democratic lawmaker Rep. Neil Abercrombie stepped down earlier this year to concentrate full-time on his bid for Hawaii governor.
The seat includes Honolulu and some surrounding suburbs. President Obama, who spent parts of his childhood in the district, won 70 percent of the vote in the 2008 presidential election.
But there were two Democratic candidates on the ballot in this election and recent polls indicate they were splitting the vote.
The results, posted on the state's Office of Elections website late Saturday, proved likewise:
State Senate President Colleen Hanabusa, considered the more liberal candidate, received 52,445 votes or 30.8 percent. She had been in third place in recent polls, but she refused to step aside.
Former Rep. Ed Case, considered the more moderate candidate, garnered 47,012 votes or 27.6 percent.
The special election was a winner-take-all contest, with only a plurality needed for victory.
National Democratic Party organizations favored Case but did not formally endorse either of their party's candidates.
The Democratic Congressional Campaign Committee ran ads that criticized Djou. But earlier this month, after it was clear neither candidate would drop out, the DCCC stopped spending any more money or time on the race.
Djou will have to defend the seat come November, and national Democrats are saving their firepower for that contest, when only one Democrat will be on the ballot.
"We're looking at November in Hawaii," Rep. Chris Van Hollen, the DCCC chairman, told reporters Thursday. "I think you all know the situation, and it's important that people do understand the unique circumstances of a special election in Hawaii - you don't have a primary. You have, in this case, three candidates - two Democrats and one Republican. I can confidently predict that the Democrats together will get a majority of the vote. Just like the Democratic candidate in November will get a majority of the vote."
But a win for Djou in the special election was seen as a symbolic victory for the GOP.
"The fact that we have an opportunity to win in President Obama's childhood district where he received 70 percent of the vote in '08, speaks to the quality of Charles Djou's candidacy and the level of Republican voter intensity across the country," Ken Spain, NRCC communications director, said last week.