WASHINGTON (AP) — Tennessee Republican Sen. Bob Corker has decided anew not to seek re-election this fall, his chief of staff said Tuesday, after spending recent weeks reconsidering his initial decision to leave the chamber where he's served since 2007.

Corker "has been encouraged by people across Tennessee and in the Senate to reconsider" his decision to retire, the senator's chief of staff, Todd Womack, said in a statement. After studying Corker's prospects, "a clear path for re-election was laid out," Womack said.

But he added, "the senator believes he made the right decision in September and will be leaving the Senate" when his term expires in January 2019.

Corker said when he first ran for the Senate in 2006 that he believed in serving two terms "because he has always been drawn to the citizen legislator model and believes public service should be missional," Womack said.

Corker's retirement sidesteps what would have been a primary battle against conservative Rep. Marsha Blackburn for the GOP nomination that promised an uncertain outcome. Corker is chairman of the Senate Foreign Relations Committee.

Tennessee leans heavily Republican but the state has a tradition of electing centrist senators like Corker. Former Gov. Phil Bredesen is expected to be the Democratic nominee, and some Republicans have worried Bredesen would have a better chance if Blackburn is the GOP candidate.

Corker said last year that under Trump, "the White House has become an adult day care center" and warned the president could put the U.S. "on the path to World War III." In what's seemed an easing of tensions, the two men have had conversations in recent weeks.

By the time Corker began rethinking his decision to leave the chamber, Blackburn and former GOP Rep. Stephen Fincher had had already filed to run in the GOP's August primary for the seat. Senate Majority Leader Mitch McConnell, R-Ky., would not say whether he'd encouraged Corker to try staying in the chamber.