Ambassador to Japan Bill Hagerty (right) would be running for the seat being vacated by retiring Republican Sen. Lamar Alexander. | Jacquelyn Martin, Pool/AP Photo elections Ambassador to Japan will run for Senate in Tennessee, Trump tweets

Bill Hagerty, the U.S. ambassador to Japan, hasn't officially announced he's running for Senate in Tennessee next year — but President Donald Trump is already on board.

Trump's tweet Friday afternoon served as both campaign rollout and presidential endorsement: Hagerty, Trump's Tennessee Victory chair during the 2016 campaign, would be running for the seat being vacated by retiring Republican Sen. Lamar Alexander.


"Tennessee loving Bill Hagerty, who was my Tennessee [Victory] Chair and is now the very outstanding Ambassador to Japan, will be running for the U.S. Senate. He is strong on crime, borders & our 2nd A. Loves our Military & our Vets. Has my Complete & Total Endorsement!" the president tweeted.

Hagerty is working through the process of departing from his current position, according to a person familiar with the operation. Veteran GOP strategist Ward Baker, a former executive director of the National Republican Senatorial Committee, will head Hagerty's campaign, according this person. Baker served as top consultant for the campaign of now-Sen. Marsha Blackburn (R-Tenn.) last year.

Blackburn and Alexander have been making calls on Hagerty's behalf, this person said.

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The endorsement from Trump comes after several other Tennessee Republicans passed on the Senate race this week. Former Gov. Bill Haslam, who left office earlier this year, declined to run, as did Republican Rep. Mark Green.

Manny Sethi, a trauma surgeon, is the most prominent Republican currently in the race, and Republican Rep. David Kustoff tweeted earlier this week that he would consider running.

Veteran and attorney James Mackler is the only Democrat in the race, though Republicans are heavily favored to hold the seat.