Senator Bob Corker, the influential chairman of the U.S. Senate Foreign Relations Committee, has announced that he is retiring from the U.S. Congress after his current term expires next year.
In a statement on September 26, Corker said he wanted to be free from the political pressures that come with facing reelection as he decides how to vote on legislation coming before the Senate in coming months.
"I believe the most important public service I have to offer our country could well occur over the next 15 months, and I want to be able to do that as thoughtfully and independently as I did the first 10 years and nine months of my Senate career," he said.
Corker, 65, is the first senator to announce his retirement ahead of the 2018 congressional elections, in which one-third of the 100-seat Senate will be up for grabs.
Trump considered asking Corker, a centrist Republican known for working with Democrats to pass legislation, to be his secretary of state, but ended up nominating Rex Tillerson.
Corker played an important role in the passage this year of legislation tightening sanctions against Russia over its alleged meddling in the U.S. election, aggression in Ukraine, and other issues.
He initially advocated giving Trump more time to seek improvements in relations with Russia, but cleared the way for the bill to pass in July by dropping his objections.
Corker has advised Trump on national-security issues but sharply criticized Trump in August following race-related violence in Charlottesville, Virginia.
"There need to be some radical changes," Corker said. "The president has not yet been able to demonstrate the stability nor some of the competence that he needs...to be successful."
Corker's criticism prompted an angry response from Trump, who said in a tweet that "Tennessee not happy" with what he called Corker's "strange" remarks.
Corker will remain chairman of the Foreign Relations Committee until he leaves the Senate in January 2019. He said on September 26 that he wanted the committee to address issues including Tillerson's reorganization of the State Department, food-aid reform, and efforts to combat human trafficking and slavery.
Corker said the committee would also address the 2015 agreement between Iran and world powers under which sanctions have been eased in return for restrictions in Tehran's nuclear activities.
Trump faces a mid-October deadline to decide whether to certify that Tehran is complying with the pact, and a decision not to certify could force Congress to decide whether to reimpose sanctions. Corker would not say whether Trump had decided to certify or not.
With reporting by Reuters and The New York Times