NATIONWIDE — Republican House Speaker Paul Ryan will not run for re-election, his office announced Wednesday, injecting another layer of uncertainty as Republicans face worries over losing their majority in the fall.

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, Ryan had made tax cuts a centerpiece of his legislative agenda, and a personal cause, and Congress delivered on that late last year.

Ryan, 48, announced his plans at a closed-door meeting of House Republicans Wednesday morning, according to those present. His tone was somber, and he read directly from prepared remarks.

“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 honor of his life, and he thanked them for the trust they placed in him.”

Ryan will serve out his term and retire in January, Buck said.

Ryan, a Republican from Janesville, Wisconsin, was first elected to Congress in 1998. Along with Reps. Eric Cantor and Kevin McCarthy, he branded himself a rising “Young Gun” in an aging party.

He became the GOP presidential nominee Mitt Romney’s running mate in 2012.

Ryan was pulled into the leadership job by the abrupt retirement of House Speaker John Boehner in 2015. Boehner had struggled to wrangle the chamber’s restless conservative wing and failed to the seal big-picture deals on fiscal policy he sought. 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 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 tighter with Trump, is expected to seeking the speaker post. He will likely compete with House Majority Whip Steve Scalise, of Louisiana, for the job. Both men spoke at the closed-door meeting Wednesday, delivering tributes to Ryan.

In Wisconsin, the most likely Republican candidate is state Assembly Speaker Robin Vos, multiple Republicans in the state said. Vos did not immediately return telephone or text messages.

Another Republican mentioned as a potential candidate is longtime Ryan family friend and Ryan backer Bryan Steil, an attorney and member of the University of Wisconsin Board of Regents. Steil did not immediately return an email seeking comment.

Democrat Randy Bryce, a colorful ironworker who has cultivated an “IronStache” moniker, had been Ryan’s best-known challenger, drawing liberal support from around the country. He had nearly $2.3 million 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 criticized as racist or anti-Semitic.

Political reactions: 

Congressman John Carter, TX-31, released the following statement:

  • “Speaker Ryan has served with distinction for almost 20 years and because of his leadership, the House has pursued a bold agenda that has ushered in a new tax code, ended sequestration and worked to rebuild our military. It has been a privilege to work alongside him and call him my friend. While his remarkable leadership in the House will be greatly missed, I wish him the very best as he embarks on this new journey with his family.”

Texas Democratic Party Chair Gilberto Hinojosa issued a statement: 

  • “The blue wave is rising while the Trump Republican Party is in full chaos. The Republican Speaker of the House leaving Congress shows the rats are jumping off the sinking ship."