US House of Representatives Speaker Paul Ryan will not run for re-election this year, in a big blow to Republicans with mid-term elections looming.
Congress' most powerful lawmaker said he would not stand for another term in his Wisconsin district this November.
Republicans already face a tough challenge from Democrats to keep control of the lower chamber.
Mr Ryan joins nearly 30 House Republicans who have announced this year they are retiring outright.
Democrats need 23 seats to take over the House.
In a Wednesday morning news conference, Mr Ryan said the decision was family-related.
"You all know that I did not seek this job," he said. "I took it reluctantly.
"But I have given this job everything. I have no regrets whatsoever for having accepted this responsibility."
He continued: "But the truth is it's easy for it to take over everything in your life and you can't just let that happen."
The 48-year-old father-of-three said he did not want to be known by his children as "only a weekend dad".
Mr Ryan said he would retire in January after finishing his congressional term.
