Tea Party-backed candidate Richard Mourdock was projected the winner over Sen. Richard Lugar (R-Ind.) in Indiana's Republican primary election on Tuesday night by NBC.
Lugar, a six-term incumbent, is the first sitting senator to be defeated in a primary contest this year. In 2010, a handful of contenders running with Tea Party support triumphed over Republican establishment-backed hopefuls.
Mourdock will face off against Democratic Rep. Joe Donnelly in a general election match-up in November.
Guy Cecil, Executive Director of the Democratic Senatorial Campaign Committee, addressed the results of the primary in a statement.
"Richard Mourdock is this year’s Ken Buck. Tonight’s results make the Indiana Senate race a toss-up race," he said. Buck ran for Senate in 2010.
While he failed to oust Sen. Michael Bennet (D-Colo.) from his post, he managed to beat establishment candidate Jane Norton in Colorado's GOP Senate primary.
Cecil continued, "Tens of thousands of Hoosiers who have voted for Dick Lugar their entire voting lives are going to reject a Tea Party candidate like Richard Mourdock and support an honest, common sense job creator like Joe Donnelly." He added, "Richard Mourdock is a right wing Tea Party ideologue who questioned the constitutionality of Medicare and Social Security, says there should be more partisanship and less compromise in Washington, and actually compared himself to Rosa Parks."
The conservative Club for Growth also addressed the outcome of the race on Tuesday night.
"The Club for Growth PAC congratulates Richard Mourdock on his historic victory over Senator Lugar," said Chris Chocola, the group's president. "Richard Mourdock defeated a legend in Indiana politics because of his hard work, focus on the issues, and his conservative message. Richard Mourdock’s victory truly sends a message to the liberals in the Republican Party: voters are rejecting the policies that led to record debt and diminished economic freedom, and they will continue to be rejected in elections throughout America."
He congratulated Lugar on his career and said, "Despite our disagreement on many issues, I have a deep personal admiration for Senator Lugar’s dedication to Hoosiers and his vast knowledge of foreign affairs."
Below, a look at some other Tea Party-backed candidates running for Senate this year.