Sen. Orrin Hatch (R., Utah), the longest-serving Senate Republican, announced Tuesday that he will retire at the end of his current term this year.
In a video addressed to his fellow Utahans, Hatch touted his accomplishments, including leading the effort to pass the Republican tax overhaul President Donald Trump signed into law last month.
Trump, Hatch said, called him a "fighter," but he said even the best ones know when to "hang up the gloves."
"For me, that time is soon approaching. That's why, after much prayer and discussion with family and friends, I've decided to retire at the end of this term," Hatch said.
He would have been up for re-election in November.
"Although I will miss serving you in the Senate, I look forward to spending more time with my family, especially my sweet wife, Elaine, whose unwavering love and support made all of this possible," he said.
"I'm deeply grateful for the privilege you've given me to serve as your Senator these last four decades," Hatch added. "I may be leaving the Senate, but the next chapter in my public service is just beginning.
Hatch, 83, has served in the U.S. Senate since 1977.
His departure leaves an opening for Mitt Romney, the 2012 Republican presidential nominee who was a sharp critic of Trump during the 2016 presidential campaign. Reports emerged last year that Romney planned to run for the Utah Senate seat in 2018 if Hatch decided not to seek another term.
Hatch is the third Republican Senator to announce he won't seek another term in 2018.
Sens. Jeff Flake (R., Ariz.) and Bob Corker (R., Tenn.) have also announced they will not run again, although they are not Trump allies like Hatch is.