(CNN) - Utah Sen. Orrin Hatch announced Tuesday that he won't seek re-election this year, clearing the way for Mitt Romney to return to the national stage by running for his seat. Romney is a resident of Utah.
He said in a social media message, "After much prayer and discussion with family and friends I've decided to retire at the end of this term."
Hatch, the Senate's longest serving Republican, has wrestled with the decision for months, emboldened by the entreaties of President Donald Trump to seek an eighth term.
Now, it sets up a potential path for Trump critic Romney, the 2012 Republican presidential nominee, to reclaim the spotlight as a conservative counterpoint to the President.
Their relationship has been complicated.
Trump has been a longtime Romney critic despite offering a 2012 presidential endorsement, and Romney has outspoken in his dissent over Trump's rhetoric and policies, calling on Republicans to block Trump's path to the presidency.
"Here's what I know. Donald Trump is a phony, a fraud. His promises are as worthless as a degree from Trump University," Romney said in a March 2016 speech. "He's playing the American public for suckers: He gets a free ride to the White House and all we get is a lousy hat."
Yet after Trump was elected, Romney was under consideration for the post of secretary of state. The two had a warm and animated conversation at a table at Jean Georges at Trump's New York hotel in November 2016 and met at Trump's golf course in Bedminster, New Jersey. Trump eventually chose Rex Tillerson instead.
White House adviser Kellyanne Conway said Trump and Romney spoke on the phone following Trump's trip to Utah last month.
But Romney has also continued to criticize the President. After Trump blamed "both sides" for inciting deadly violence in Charlottesville, Virginia, last summer, Romney said Trump's remarks "caused racists to rejoice."
In a statement, Romney praised Hatch's service but did not mention anything about a possible Senate run.
I join the people of Utah in thanking my friend, Senator Orrin Hatch for his more than forty years of service to our great state and nation," Romney said in a Facebook post. "Ann and I wish Senator Orrin Hatch and his loving wife Elaine all the best in their future endeavors."