Brown’s abrupt decision, while not surprising to some GOP insiders who knew he was wavering, stunned the rest of the political world and delivered a major blow to Republican Party leaders who saw in him their best chance to win the June 25 election. It came with little warning to national or state leaders, who had been pleading with Brown to run, and caused a furor within state party ranks.

Scott Brown, who burst onto the ­national scene as a political celebrity with his upset victory in 2010, upended the special US Senate election with an announcement Friday that he will not run to replace John F. Kerry.


Brown’s first public disclosure that he was withdrawing from the race was oddly frivolous for such a momentous decision, with far-reaching implications. It came in a text message to a friendly ­Boston Herald columnist. “U r the first to know I am not running,” he wrote.

Brown’s move dramatically reshapes what had been expected to be a competitive campaign that would draw huge ­national attention. Recent polls show Brown remains highly popular despite his unsuccessful bid to retain his Senate seat last fall. He also had a campaign and fund-raising structure still in place from that race against Elizabeth Warren.

With Republicans struggling to find another strong candidate, the Democratic primary between Edward J. Markey and Stephen F. Lynch quickly takes on greater importance. The GOP is suddenly grasping for alternatives, hoping to press ­into service known figures such as former governor William F. Weld, former lieutenant governor Kerry Healey, or Richard R. Tisei, the former state Senate minority leader.

“I think everybody’s just caught off guard today,’’ said ­Tisei, who acknowledged that he is weighing a campaign. “I hope at the end of the day that there will be a strong Republican candidate.”


In his formal statement, Brown cited the hyperpartisanship in Washington and the prospect of a grueling third campaign in just a few years. If he ran and won, Brown would then have to immediately gear up for a fourth campaign ahead of the 2014 election, to win a full term.

“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,” Brown said in a statement. “And I know it’s not the only way for me to advance the ideals and causes that matter most to me.”

Brown, 53, a Wrentham resident who was a state senator and a small town real estate conveyance lawyer before he catapulted into the US Senate, has told associates he wants to cash in on his political celebrity to land a high-paying job in the private sector, probably as a rainmaker at a powerful law firm.

Gleeful Democrats greeted Brown’s move Friday with taunts to the GOP that it could not field a viable candidate, while Republicans tried to put the best spin on what could be a huge setback for the party, which has hope of capturing control of the US Senate in 2014.

Republicans will need to find a candidate soon for the June 25 election. To make the April 30 primary ballot, candidates must gather 10,000 certified signatures in four weeks.


Brown had long been considered the party’s strongest and most plausible candidate.

State Representative Daniel Winslow, a Norfolk Republican, said he will also take the next few days to consider a potential run. Gabriel E. Gomez, a wealthy businessman and a former Navy SEAL and fighter ­pilot from Cohasset, said he is very likely to get into the race.

The manner in which Brown opted out of the race Friday created a ruckus within state party ranks. He had spent weeks lobbying the Republican State Committee to appoint his former deputy campaign finance chairman, Kirsten Hughes, as its new chairman Thursday night.

Brown’s strong appeal to the committee members, which ­included the argument that he would need her to help him win the special Senate race, was critical in Hughes’s razor-thin margin of victory.

Party activists who voted for Hughes based on that plea felt blindsided by Brown’s quick pivot. The hard feelings could blemish Brown’s influence within the state party.

“One of the reasons for voting for Kirsten was that Scott Brown was running for the Senate and needed her to be there,” said Steve Aylward, who supported Hughes’s opponent. “Now one day afterward, he ­decides not to run for it? I think I’m speaking for a lot of the grass-roots activists who are going to say, ‘This doesn’t pass the smell test.’”

Hughes, according to two GOP leaders who had spoken to her, was caught off guard by Brown’s announcement and was informed shortly before it was made public.


Colin Reed, a Brown spokesman, said neither he nor Brown would comment on the subject.

National Republicans were also caught unaware. The ­National Republican Senatorial Committee had begun coordinating efforts this week to get Brown’s former senior GOP Senate colleagues to press him to run.

But Brown told executive ­director Rob Collins only a few hours before he made his decision public early Friday afternoon, according to a state ­Republican official who talked to Collins.

National and state Republicans nonetheless tried to close ranks Friday afternoon. In a statement, Collins said the party “remains excited about the prospect of the Massachusetts special election, and we have the organization, energy, and resources to win.’’

He then pointed to the tough Democratic primary battle between Markey and Lynch as a good sign for the GOP.

“As the Democratic primary between Representatives Ed Markey and Stephen Lynch turns uglier and nastier each day, the Massachusetts special election provides a real pickup opportunity for Republicans, and we intend on defeating whichever career politician limps through,” said Collins.

Michael Levenson of the Globe staff contributed to this report.