DENVER — Sen. Michael Bennet narrowly defeated tea party Republican Ken Buck on Wednesday, allowing Democrats to hold onto a Senate seat once viewed as a prime opportunity for the GOP to make gains.
Bennet provided a crucial firewall during midterm elections in which Republicans made a historic surge. But his win looked anything but certain.
The Colorado race attracted more out-of-state campaign money than any other Senate contest this year, prompting a stream of vicious attack ads as both parties viewed the contest as the one that could tip the balance of power in Congress.
Buck, an affable campaigner whose folksy charm launched him over a better-funded Republican primary opponent, had a small lead heading into the election, according to many polls.
But with 97 percent of the projected vote counted Wednesday, Bennet was leading by about 15,400 votes out of 1.4 million cast.
Bennet himself seemed pleasantly surprised when he declared victory. He talked about the national anti-incumbent mood, and the perception that Republicans would rack up victories all across the country.
"When they get to Colorado, let me tell you, they're not going to know what happened," Bennet said Wednesday in a victory speech outside the Denver museum where President Barack Obama last year signed the stimulus bill into law.
More than a hundred Democrats packed the plaza to cheer for the party's better-than-predicted performance here. Democrats lost two House seat to the GOP, but one vulnerable House Democrat in the Denver suburbs hung on, and the party's gubernatorial candidate, Denver Mayor John Hickenlooper, won easily in a three-way contest.
Left-leaning Democratic allies also succeeded in defeating a raft of Colorado ballot measures proposed by conservatives, including a measure outlawing abortion and a trio of measures to reduce taxes and government borrowing.
The Senate win came after Bennet drubbed Buck as an out-of-touch extremist.
Bennet and Democratic allies reminded Colorado's moderate voters that Buck opposes abortion, even in cases of rape and incest; that he had questioned the separation of church and state; and that he said sexual orientation is a choice. The too-extreme-for-Colorado theme helped counter heavy spending from outside conservative groups.
Buck conceded the race with a message on his Facebook page.
"While the final margin in the race is very small, Colorado voters have spoken," Buck wrote.
Bennet, 45, was appointed to the seat last year to replace Ken Salazar, who became Interior Secretary. Before his appointment, Bennet was superintendent of Denver Public Schools and had never run for public office.
Democrats retained control of the Senate on Tuesday, though they lost at least six seats to the GOP. Senate races in Washington and Alaska were too close to call Wednesday.