After more than a year of bitterness between the president and his former attorney general, President Trump landed a heavy blow to Jeff Sessions’s pursuit of his old Senate seat in Alabama.

Trump endorsed his former ally’s rival, retired college football coach Tommy Tuberville, on Tuesday ahead of this month’s Republican primary runoff to see who will challenge Sen. Doug Jones (D-Ala.) in November.

“Tommy was a terrific head football coach at Auburn University,” Trump tweeted Tuesday evening, nearly a week after the Republican primary in Alabama determined Sessions and Tuberville would be headed to a runoff. “He is a REAL LEADER who will never let MAGA/KAG, or our Country, down!”

Heavily implied in Trump’s tweet was another important constituency he believes Tuberville would not disappoint: the president himself.

“Coach Tommy Tuberville, a winner, has my Complete and Total Endorsement,” he added in another tweet.

Trump has been attacking Sessions since the he recused himself from the Justice Department’s investigation of Russian interference in the 2016 election. Sessions was a major adviser to the Trump campaign in 2016 and thus, Sessions said, barred from investigating it by a Justice Department rule.

The decision roiled Trump, who felt betrayed by one of his earliest and staunchest backers. He publicly berated Sessions and ultimately forced him out of his Cabinet.

Sessions was the first senator to endorse Trump in 2016. He helped legitimize Trump’s campaign early on, when few GOP politicians openly backed the party outsider. Trump once called him “someone I’m very proud to call a friend.”

Trump reportedly called Sessions a “dumb Southerner” and mocked his regional drawl. Privately, the president reportedly called him “Mr. Magoo,” an old, bald cartoon character who obstinately refused to acknowledge his poor eyesight, among other shortcomings. Publicly, on Twitter, he called Sessions a “beleaguered attorney general,” who had taken “a VERY weak position” and “should be ashamed of himself.”

The president’s endorsement may be critically important in a state where Republican voters enthusiastically back Trump. Early Wednesday, Sessions resorted to reassuring voters that the Trump administration has his full support, even if he does not have the president’s backing.

“Even before he declared for the presidency, I fought for the principles that Donald Trump so effectively advocated in the campaign and has advanced as President,” Sessions said on Twitter on Wednesday, defending his candidacy. “I believed in those principles then, I have always fought for them, and I will continue to do so.”

Despite the public barbs Trump has flung at Sessions, the former attorney general has refused to criticize the president, who won in Alabama by more than 27 percentage points in 2016. In his first campaign commercial, Sessions played up his loyalty to the president in an ad one observer said was aimed at an “audience of one.”

“When I left President Trump’s Cabinet, did I write a tell-all book? No!” Sessions said in the campaign ad. “Did I go on CNN and attack the president? Nope! Have I said a cross word about our president? Not one time.”

Some Republicans had hoped Trump would stay out of the Alabama Senate race. Sessions has aimed to take back the Senate position from Jones, the Democrat who flipped the longtime GOP seat during a 2017 special election to replace Sessions.

Jones defeated former judge Roy Moore, the Republican candidate who was accused of sexually abusing teenage girls while working as district attorney in the 1970s.

But Trump’s disdain for Sessions opened him up to challenges from within the Republican Party. Several other candidates also opposed Sessions, but only Tuberville, the former Auburn coach, came out ahead of him. Tuberville netted 33.4 percent of the vote, followed by Sessions with 31.6 percent.

Now, with Tuberville and Sessions set to compete in a runoff, Trump’s endorsement could boost the former coach’s campaign.

“Looking forward to helping you drain the swamp and #KAG!” Tuberville tweeted in response to Trump, referring to the president’s 2020 campaign slogan, “Keep America Great.”