US House Speaker Paul Ryan will not run for re-election, his office has announced, injecting another layer of uncertainty as Republicans face worries over losing their majority in the autumn.
Republican Mr Ryan’s plans have been the source of much speculation and will set off a scramble among his lieutenants to take the helm.
A self-styled budget guru, Mr Ryan had made tax cuts a centrepiece of his legislative agenda and a personal cause, and Congress delivered on that late last year.
Mr Ryan, 48, announced his plans at a closed-door meeting of House Republicans on Wednesday morning.
“After nearly 20 years in the House, the Speaker is proud of all that has been accomplished and is ready to devote more of his time to being a husband and a father,” Ryan adviser Brendan Buck said in a statement.
“While he did not seek the position, he told his colleagues that serving as Speaker has been the professional honour of his life, and he thanked them for the trust they placed in him.”
Mr Ryan will serve out his term and retire in January, Mr Buck said.
Mr Ryan, a Republican from Janesville, Wisconsin, was first elected to Congress in 1998.
Along with Representatives Eric Cantor and Kevin McCarthy, he branded himself a rising “young gun” in an ageing party.
He became Republican presidential nominee Mitt Romney’s running mate in 2012.
Mr Ryan was pulled into the leadership job by the abrupt retirement of House Speaker John Boehner in 2015.
Mr Boehner had struggled to wrangle the chamber’s restless conservative wing and failed to seal big-picture deals on fiscal policy he sought.
Mr Ryan had more trust with the hardliners in the House, but had no more success in brokering fundamental reform of entitlement he sought.
He ultimately had to wrestle with another unexpected challenge: President Donald Trump, a president with little of Mr Ryan’s interest in policy detail or ideological purity. The two have had not had a close working relationship.
House Majority Leader McCarthy, a Republican from California known to be closer to Mr Trump, is expected to seek the Speaker post.
He will probably compete with House Majority Whip Steve Scalise, of Louisiana, for the job.
Both men spoke at the closed-door meeting on Wednesday, delivering tributes to Mr Ryan.
In Wisconsin, the most likely Republican candidate is state Assembly Speaker Robin Vos, multiple Republicans in the state said.
Another Republican mentioned as a potential candidate is longtime Ryan family friend and Ryan backer Bryan Steil, a lawyer and member of the University of Wisconsin Board of Regents.
Democrat Randy Bryce, a colourful ironworker who has cultivated an IronStache moniker, had been Mr Ryan’s best-known challenger, drawing liberal support from around the country.
He had nearly 2.3 million dollars in the bank at the end of the first quarter.
Janesville teacher Cathy Myers was also running on the Democratic side.
The only declared Republican was Paul Nehlen, who was banned from Twitter for a series of posts criticised as racist or anti-Semitic.