Wisconsin Rep. Paul Ryan told House Republicans late Tuesday that he will run for House Speaker if he is the unity candidate of the divided party.
Ryan spoke to the House GOP behind closed doors and said if all factions can share his vision and he can get the endorsement of the major caucuses, then he will serve as speaker.
In a statement released by the Wisconsin congressman, Ryan said he then "will be all in."
The 45-year-old Ryan, under intense pressure to seek the post, gave his colleagues until Friday to express their support.
"Congressman Ryan has said he's willing to serve" if he can get support from the House Freedom Caucus and other groups, said Rep. Darrell Issa, R-Calif.
Ryan, the GOP's 2012 vice presidential nominee, had consistently said he does not want to be speaker and would prefer to stay on as chairman of the tax-writing Ways and Means Committee, which he's described as his dream job.
But he's been under heavy pressure to reconsider from Speaker John Boehner and other party leaders who argue he is the only House Republican with the stature and broad popularity to unite a caucus divided against itself, at a moment of deep turmoil.
Congress is hurtling toward an early November deadline to raise the federal borrowing limit or invite a first-ever default, and a deadline to pass spending legislation or risk a government shutdown will follow in early December.
Ryan met with members of the Freedom Caucus at their request, his spokesman said. This group of three dozen or so hardline conservatives pushed Boehner to announce his resignation by threatening a floor vote on his speakership, and scared off Boehner's No. 2, Majority Leader Kevin McCarthy, who abruptly withdrew from the speaker's race just before the recess.