Louisiana GOP Sen. David Vitter won’t seek reelection in 2016, after losing the state governor’s race Saturday.
The two-term senator lost to state Democratic Rep. John Bel Edwards in the runoff election.
“I've reached my personal term limit," Vitter reportedly told supporters after losing to Edwards, who won about 56 percent of the vote.
Edwards and Vitter were the top-two vote-getters in last month’s open primary with seven other contenders. But Edwards was forced into the one-on-one contest with Vitter because he failed to get 50 percent of the vote.
Potential GOP candidates in the race to replace Vitter after he finishes his term next year include Reps. Charles Boustany and John Fleming.
Louisiana Democrats rejoiced in Edward’s upset victory -- reclaimed the governor's mansion for the first time in eight years.
His victory was once-unthinkable in the conservative state and a stunning turn of events for Vitter, who started his campaign nearly two years ago as the race's front-runner.
Edwards' win was also a rare pick-up of a governor's seat for Democrats in the conservative Deep South.
But Republican leaders insisted it was a one-time fluke that didn't suggest the GOP was on the ropes in Louisiana.
“Make no mistake, Louisiana is a deep red state, and our Republican brand is strong," said state GOP party Chairman Roger Villere, who pointed to victories Saturday in the races for lieutenant governor and attorney general and gains made in the state legislature.
However, he acknowledged the Vitter loss was "disappointing.”
The Democratic victory was as much about Vitter's flaws as a candidate as it was about Edwards' strengths.
Edwards painted the race as a referendum on Vitter's character and suggested the senator didn't measure up in such a competition.
Edwards, who started the campaign as a little-known lawmaker from a rural parish, focused on his West Point degree and military resume, and he pledged a bipartisan leadership style.
"The people have chosen hope over scorn, over negativity and over distrust of others," Edwards said in his victory speech.
In the final days, Vitter sought to rally Republican voters by drawing policy distinctions with Edwards and making Syrian refugee resettlement an issue in the state campaign. But it didn't work.
Rather than a race about the state's deep financial troubles, the contest for governor largely became about Vitter, who has been in elected office, first as a state lawmaker and then in Congress, for more than 20 years.
Vitter began the election cycle nearly two years ago as the clear favorite. He stockpiled cash for the campaign, dwarfing all competitors. And with a campaign operation that has helped him and his allies to steamroll opponents over the years, he appeared nearly unbeatable.
But Vitter was hit with repeated attacks for a 2007 prostitution scandal in which he apologized for a "serious sin" after he was linked through phone records to Washington's "D.C. Madam."
He had trouble uniting Republicans after a blistering primary competition in which Vitter trashed two GOP rivals and received heavy criticism for his scorched-earth political style. And his campaign was accused of ethical improprieties after allegations it secretly recorded political opponents. Vitter's negatives with voters shot up in the polls.
The senator also was hampered by high disapproval ratings for his fellow Republican, outgoing Gov. Bobby Jindal, who is blamed for the state's financial problems.
"John Bel Edwards' victory shows that Louisiana has turned the page on David Vitter's scandals and eight years of Bobby Jindal's failed economic policies," the Democratic National Committee said in a statement.
The Associated Press contributed to this report.