First he’s out, then maybe he’s in, and then … yeah, Bob Corker’s out. The previously retiring senator from Tennessee has decided to stick with retirement, his chief of staff told Politico. Todd Womack said a two-term limit was always Corker’s plan anyway:

Sen. Bob Corker (R-Tenn.) will not run for reelection after reconsidering his decision last fall to retire, his chief of staff said Tuesday.

After listening to some Tennessee Republicans and GOP senators who were privately urging him to run, the two-term senator and Foreign Relations Committee chairman decided that this will be his last year as senator, said Todd Womack, Corker’s chief of staff. The move ends a period of intense speculation in Tennessee and Washington about Corker’s future and avoids what could have been an ugly primary between Corker and Republican Rep. Marsha Blackburn.

“He’s always believed and served as though he were only going to be in the Senate for two terms,” Womack said in an interview. “And he was willing to listen to folks but he really believes the decision he made in September was the right one and is going to be leaving the Senate at the end of the year.”

Did he? Curiously, Corker has been fundraising rather successfully during his second term, which appeared to indicate — at least until September — that a third term was in the offing. His quarterly filing with the FEC from earlier in the month showed no activity in the fourth quarter of 2017 after his retirement announcement, as one might expect, but Corker had already amassed $6.2 million cash on hand for a 2018 run. His campaign committee had nearly $124,000 in operating expenses in Q4, indicating a low level of activity, but has spent almost $2.2 million over the election cycle. That’s an awful lot of money coming in and going out for a man who was planning to retire all along.

Blackburn, who benefits most from Corker’s reversion to retirement, offered well wishes to her potential rival:

Blackburn thanked Corker for his service Tuesday.

“Now, we can unify the Republican party and focus on defeating Democrat Phil Bredesen in November,” Blackburn said in a statement. …

In the days since Corker confirmed he was taking another look at the race, the Blackburn team has touted a series of endorsements and polls to try to show she’s locked up GOP support in the state.

Lt. Gov. Randy McNally endorsed Blackburn last week, along with two-thirds of GOP state senators. The Club for Growth and Americans for Prosperity have said they’d stick with Blackburn if Corker got back in the race.

It would have been tough but not impossible for Corker to get back in the race, or at least not unprecedented. Marco Rubio did it in 2016 at the last minute after Florida Republicans begged him to reconsider his plans to go back into the private sector after the presidential primary loss to Donald Trump. However, Rubio didn’t face the kind of contentious primary with an opponent as credible as Blackburn. Rubio coasted to an easy victory over Democrat Patrick Murphy in the general election, in large part because he was able to unite Republicans quickly behind his candidacy.

Corker’s jump back into the primary would have split the GOP and damaged everyone, and it would have been Corker’s fault. Perhaps Blackburn would have challenged Corker in the primary anyway, but his announcement last September opened the door for her to move up to the Senate without taking aim at an incumbent from her own party. She’s giving up an easy hold in the House, and a reversal from Corker would have left her twisting in the wind.

In the end, Corker’s making the right decision by sticking with his first decision. It will be interesting, though, to see where Corker decides to spend his $6.2 million in campaign cash. Does he back Blackburn, or will he choose to avoid the race altogether? We may need to wait for a couple more quarterly filings to find out.