Ken Buck is likely headed to Washington after all. 

The 2010 Senate nominee, who was maligned in his race four years ago against Sen. Michael BennetMichael Farrand BennetDemocrats protest Trump's immigration policy from Senate floor On The Money — Sponsored by Prudential — Senators hammers Ross on Trump tariffs | EU levies tariffs on US goods | Senate rejects Trump plan to claw back spending Senators hammer Ross over Trump tariffs MORE (D-Colo.), won the open 4th District House GOP primary Tuesday night. Now, Buck is the odds-on favorite in the fall to succeed Rep. Cory GardnerCory Scott GardnerSenate moving ahead with border bill, despite Trump 13 GOP senators ask administration to pause separation of immigrant families Sessions floats federal law that would protect states that decriminalize marijuana MORE (R-Colo.), who is running for Senate. 

ADVERTISEMENT
The Associated Press has called the race for Buck, who had 44 percent of the vote with 58 percent of precincts reporting. Buck's closest opponent, state Sen. Scott Renfroe, took just 24 percent despite winning the top spot on the ballot at the district convention. 

Still, Buck was perceived to be the favorite headed into the primary. He had originally been seeking to unseat Sen. Mark UdallMark Emery UdallSenate GOP rejects Trump’s call to go big on gun legislation Democratic primary could upend bid for Colorado seat Picking 2018 candidates pits McConnell vs. GOP groups MORE (D-Colo.) this year but dropped out of the race when Gardner announced his candidacy. Gardner himself endorsed Buck to succeed him shortly after entering the Senate race.

Along with Gardner's endorsement, Buck had outraised all of his primary opponents, collecting more money than his three competitors combined. Supporters donating to Buck's campaign were the KochPAC, linked to billionaire brothers David and Charles Koch, and outgoing House Majority Leader Eric CantorEric Ivan CantorThe Hill's Morning Report — Sponsored by CVS Health — Trump’s love-hate relationship with the Senate Race for Republican Speaker rare chance to unify party for election Scalise allies upset over Ryan blindside on McCarthy endorsement MORE's (R-Va.) leadership PAC.

Buck will go on to face Democrat Vic Meyers and Libertarian nominee Jess Loban in the general election, but he’s expected to easily win in the GOP-leaning district.