Former Sen. Scott Brown, long considered to be the most likely GOP candidate for the upcoming Massachusetts special election, announced Friday he has decided against seeking the seat vacated Friday by Sen. John KerryJohn KerryInterior chief: ‘We will have climate refugees’ "Lebanizing" Syria Why Obama's 'cold peace' with Iran will turn hot MORE (D).
In a statement, Brown said he had given "serious thought" to running.
But Brown, who was elected to the Senate in 2010 but lost his seat in November, cited concerns about the repercussions of mounting multiple campaigns in a short time as a chief reason he decided against running again. He also cited a lack of interest in rejoining an increasingly fractured Congress.
“I was not at all certain that a third Senate campaign in less than four years, and the prospect of returning to a Congress even more partisan than the one I left, was really the best way for me to continue in public service at this time. And I know it’s not the only way for me to advance the ideals and causes that matter most to me," he said.
With Brown opting out of the race, Republicans face an even tougher fight to pick up the seat.
Attention now falls to a handful of potential contenders, including former Massachusetts Gov. Bill Weld (R), who the Boston Globe reports is not interested, and former Lt. Gov. Kerry Healey, who sources say is disinclined to run.
The National Republican Senatorial Committee is already looking at its options, one committee source told The Hill. The committee will be meeting with local businessman Gabriel Gomez next week to discuss a possible run, and is looking closely at former GOP House contender Richard Tisei, who lost narrowly to Rep. John Tierney (D-Mass.) last cycle.
Gomez did not respond to a request for comment. But Tisei recently told The Hill that he would be open to a run, "if there was a path to win."
And on Friday, he issued a release reiterating that he is considering running.
"Scott's exit from the race was obviously unexpected. That said, in the coming days I will be talking with family, friends, and supporters to consider the best role that I can play in helping to bring new, alternative leadership to Washington," he said in the statement.
And former Mass. State Treasurer Joe Malone (R) told The Hill he was not interested in running, though he had been contacted by a number of people urging him to jump in the race.
"If nominated I will not run. If elected I will not serve," he said.
Another possible Republican contender, former gubernatorial candidate Charlie Baker, recently ruled out a run.
Democrats are gearing up for a primary to decide their nominee; Reps. Edward MarkeyEd MarkeyNew House caucus will help keep hackers out of cars Overnight Tech: Email privacy bill gets its day FDA should ban powdered caffeine, Dems say MORE and Stephen Lynch both have launched bids for the seat.
Massachusetts Gov. Deval Patrick (D) this week appointed his former chief of staff, William "Mo" Cowan, to fill the seat vacated by Kerry, who on Friday replaced Hillary ClintonHillary Rodham ClintonNeNe Leakes: 'Donald, cut your s--t out' Sanders drops lawsuit against DNC Trump predicts easy win in November MORE as secretary of State.
In 2010, Brown took over the seat left open following the death of longtime Sen. Edward Kennedy (D). But he lost the seat in November to Elizabeth WarrenElizabeth WarrenSanders-Warren ticket would sweep the nation With either Trump or Clinton, average American loses again Elizabeth Warren stumps, raises funds for Duckworth MORE (D).
Though Brown lost to Warren, he was widely considered the strongest contender for the seat, and his choice to stay out of the race will complicate the GOP's efforts to regain it.
Former Lt. Gov. Kerry Healey could also run, but she has given no indication she will jump in the race. Former GOP congressional contender Richard Tisei, who was narrowly defeated in his bid to take over Rep. John Tierney's (D-Mass.) seat, said he would be open to a run.
According to The Boston Globe, national Republicans had recently begun what the newspaper described as a "full court press" to convince Brown to run.
Despite losing a top recruit in the race, the National Republican Senatorial Committee remained bullish Friday on their chances in the race.
NRSC Executive Director Rob Collins said that "as the Democratic primary between Reps. Ed MarkeyEd MarkeyNew House caucus will help keep hackers out of cars Overnight Tech: Email privacy bill gets its day FDA should ban powdered caffeine, Dems say MORE and Stephen Lynch turns uglier and nastier each day, the Massachusetts special election provides a real pick-up opportunity for Republicans."
Collins added that "it's time to move forward" with the race.
"This was no doubt a tough personal decision for Senator Brown and his family, who understandably need to recharge after several long, hard-fought campaigns. Now that he has made a decision, it’s time to move forward," Collins said in a statement.
"The Republican conference remains excited about the prospect of the Massachusetts special election, and we have the organization, energy and resources to win."
Had Brown ran in and won the upcoming special election, he would have had to launch yet another race in 2014.
Lynch, in a statement on Brown's decision, said he understood the difficulties inherent in running multiple, frequent campaigns.
“I understand Scott Brown’s decision. He has basically been campaigning non-stop for three years. It’s perfectly understandable that he wouldn’t want to undertake another campaign. I wish all the best to Scott and his family," Lynch said.
The Massachusetts special election primary will take place on April 30 with the general contest on June 25.
— Updated at 2:15 p.m.