Former attorney general Jeff Sessions announced Thursday night that he will run for his old U.S. Senate seat in Alabama and made clear his first priority is putting to rest tensions with President Trump.

In a video declaring his candidacy, Sessions focuses not on his tenure or his vision, but rather his enduring support for the president.

“When I left President Trump’s Cabinet, did I write a tell-all book? No. Did I go on CNN and attack the President? No. Have I said a cross word about President Trump? No,” Sessions says. “As everyone knows, President Trump and I have had our ups and downs. But here’s the important part: The president is doing great work for America.”

Sessions, an early supporter of Trump’s run for president, served as Trump’s first attorney general but fell out of favor with the president when he recused himself from overseeing the Justice Department’s Russia investigation. Their relationship never recovered and culminated with Trump unceremoniously firing him in November 2018.

Sessions’s desire to mend relations with the president at the onset of his campaign shows how damaging it is for a Republican to have Trump as an antagonist, especially in a Republican primary.

Sen. John Cornyn (R-Tex.) said he warned Sessions during a recent conversation about his potential candidacy that he needed to make up with Trump.

“He is a friend of mine. I’ll be doing everything I can to encourage him,” Cornyn said. “The problem, as I pointed out to him, is, ‘I think your life is going to be very difficult unless you work out some sort of reconciliation with the president.’ ”

Trump has threatened to attack Sessions if he enters the race, telling Senate Republican leaders that he didn’t want his ally-turned-foe to run in what already promises to be a contentious primary. Trump didn’t mention Sessions during a donor event Thursday evening for the Senate Leadership Fund, the main super PAC dedicated to electing Republicans to the Senate, according to a person in attendance.

The seat, which Sessions easily held for two decades before leaving for the Trump administration, is filled by a Democrat. Doug Jones won the seat from a traditionally conservative state in a special election in 2017, beating Republican Roy Moore, whose Senate bid fell short amid allegations of sexual misconduct with teenage girls in the 1970s. Moore is running again, joined by Rep. Bradley Byrne and several other Republicans in the state.

Jones was asked about Sessions’s candidacy during an interview Thursday on SiriusXM’s “The Joe Madison Show.”

“Before he challenges me, he’s got about six challengers in that Republican primary that are already sniping at him. . . . It’s going to be a really divisive primary,” Jones said. “And now you’ve got somebody else jumping in there that the president of the United States has said it was the biggest mistake he’s ever made by appointing him.”

Senate Majority Leader Mitch McConnell (R-Ky.) has shared concerns that Sessions’s running could create a messy primary contest for a seat that Republicans say they have to win back, according to people familiar with the matter who spoke on the condition of anonymity to discuss the issue. Trump has repeatedly denigrated Sessions to allies and White House aides in recent days, people familiar with his comments said.

Sen. Lindsey O. Graham (R-S.C.), one of Trump’s closest allies on Capitol Hill, called Sessions a “fine man” but added that he wouldn’t endorse him in the primary.

“The whole campaign’s going to be around what President Trump said about Jeff Sessions,” Graham said. “I think Jeff knows what he’s getting into and we’ll leave it up to the voters of Alabama.”

Sessions appeared on Tucker Carlson’s show on Fox News after releasing his campaign video and said he hoped to have Trump’s support. Sessions said he understood how “painful” the Russia investigation was for the president and that Trump saw Sessions’s recusal as a “pivotal moment.”

Sessions accused GOP senators of not doing enough to advance Trump’s agenda.

“I think some of them are still standoffish. Some of them almost give the impression that maybe he’ll just fail or it won’t happen and we won’t have to deal with it,” Sessions told Carlson.

Ahead of Sessions’s formal announcement, Republican senators offered tepid support for their former colleague’s attempt at a comeback.

Many GOP senators demurred when asked about his possible run, saying they didn’t involve themselves in other races’ primary contests — even for someone who served with them for years. Others voiced praise of Sessions’s previous work as a senator but also trepidation about his acrimonious relationship with Trump.

Behind the scenes, Sen. Richard C. Shelby (R-Ala.) has been working to secure endorsements from Senate Republicans, according to two senators who spoke on the condition of anonymity to describe private conversations, and has told other Republicans privately for weeks that if Sessions chooses to run, he would support him and aid him.

Sen. Roy Blunt (R-Mo.) was among the few who openly stated their support for a Sessions run. Asked whether Trump’s attacks on Sessions would hurt him given the president’s popularity in the state, Blunt said Sessions had “been pretty popular in Alabama himself.”

Others shied away from backing Sessions, instead saying they’d wait until after the primary to throw their support behind a candidate.

“I generally in primaries ­haven’t gotten involved. Not even in my state. I’d have to look at it if he ultimately makes a decision,” Sen. Thom Tillis (R-N.C.) said. “The only thing I will say about Alabama is that I am an anyone-but-Moore supporter.”

Sen. Kevin Cramer (R-N.D.) had a similar lukewarm reaction.

“I have all I can do to keep track of me. He should do whatever he wants to do,” Cramer said. “He’s free to run if he wants to run.”

When asked whether Trump’s scorn would hurt Sessions’s chances, Cramer said: “Well, I guess I’d rather go into a Republican primary with the president’s support than without it, but Jeff Sessions is iconic and, you know, obviously a player right out of the chute. But I don’t know.”

Asked what Sessions could do to win back Trump’s support, Cramer replied, “Win.”