President Trump was once bitten in Alabama, and now Senate Republicans are hoping he will be twice shy about wading into that state’s GOP primary, especially with a bunch of them supporting their former colleague, Jeff Sessions.

Sessions, the onetime senator and attorney general who went from Trump’s top ally to his foremost enemy, is trying to rewrite the end of his career by winning back his old Senate seat, beginning with Tuesday’s initial primary vote.

The victor gets the chance to run against Sen. Doug Jones (D-Ala.), who won Sessions’s seat in a December 2017 special election after Trump made a late endorsement of Roy Moore, the former judge who had been accused of sexually inappropriate behavior with teenagers in the 1970s.

But Sessions, 73, has to defeat a collection of Republican rivals, including a pair of well-funded candidates. That sets up the likelihood of no candidate receiving more than 50 percent of Tuesday’s vote and sending the race to a March 31 runoff for the top two vote-getters.

And once the race narrows to two candidates — Sessions appears to be the most likely to come in first place Tuesday, based on public and private polling — all eyes will be watching Trump to see if he endorses the other candidate as a form of retribution against his former attorney general.

“I just would be surprised. Senator Shelby has asked the president to stay out, and I think the president wants to win the seat, and I would be surprised if he jumped in a runoff,” Sen. Lindsey O. Graham (R-S.C.), a Trump confidant, said Thursday.

Sen. Richard C. Shelby (R-Ala.) has learned to take nothing for granted when it comes to the president, especially when it involves his feelings about investigations into his 2016 campaign. Trump blames Sessions for recusing himself from the Justice Department investigation that led to former special counsel Robert S. Mueller III’s two-year probe into Russian ties to the White House.

“I would hope he wouldn’t, but if he does, we’ll see. But I think that it’s Sessions’s race to win. I think it’s his,” Shelby said.

Shelby, 85, who is probably retiring when his term ends in 2023, led a group of 11 Republicans who immediately endorsed Sessions when he announced in November that he was running for his old Senate seat.

Half of that contingent were longtime Republicans who either already announced retirement plans or are considering them, the types of veteran incumbents who are not worried about infuriating Trump supporters in their state.

“He’s a brilliant man that understands how things happen. He’s been involved in a lot of issues. He would be outstanding,” Sen. Mike Enzi (R-Wyo.), who was part of the 1996 class with Sessions, said Thursday. Enzi is retiring at the end of this year.

The other half are senators with potentially many years left in the Senate, including a pair of lieutenants in Majority Leader Mitch McConnell’s leadership teams, Sens. John Barrasso (R-Wyo.) and Roy Blunt (R-Mo.).

McConnell (R-Ky.), Graham and most of Trump’s closest Senate allies have remained neutral in the race.

But Sessions has a reservoir of goodwill left in the chamber where he served for 20 years, forging a reputation as being genuinely nice to colleagues even as he developed a staunch America-first vision that was out of step with most of their ideologies.

Trump put that agenda on political steroids in his 2016 campaign, appointing one of Sessions’s closest advisers, Stephen Miller, to oversee that portfolio, including immigration, in the White House.

“He’s a good man, he’s a good man,” Sen. John Cornyn (R-Tex.), whose wife is close friends with Sessions’s wife, said Thursday of his former colleague. “I just — it’s a regrettable set of circumstances at the AG’s office, but he was a solid senator and it would be good to have him back.”

Those circumstances have provided the opening for Rep. Bradley Byrne (R) and former Auburn University football coach Tommy Tuberville to mount serious campaigns against Sessions, at least hoping that if they make the runoff against Sessions, Trump would step in with an endorsement just to embarrass his former attorney general.

That theme has dominated the national attention to the race — in Trump’s mind, Sessions recused himself, and his deputy, Rod J. Rosenstein, then appointed Mueller, whose probe did not lead to any core charges.

So it’s created the sense of every candidate trying to position themselves as the most pro-Trump Republican, right down to Tuberville driving around in a motor coach with “TUBERVILLE + TRUMP 2020” displayed on its back.

Even Sessions has pledged loyalty to Trump in the campaign, despite getting fired by him in November 2018 after months of public humiliation.

Polling has been sparse in this race, falling on the same day as the Democratic presidential nominating contest’s Super Tuesday, which includes Alabama and 13 other states. But all sides agree that Sessions has been the front-runner for months but well below the 50 percent mark that would clinch the race Tuesday.

Tuberville, trying to run as an outsider with no experience, got out to an early advantage to be the second-place finisher with Byrne lurking in the backdrop.

Moore, who is running again, has been a nonfactor in the campaign.

In recent weeks, Sessions started feeling the heat from the two upstarts, launching an ad with clips of Tuberville telling an audience that Trump was to blame for problems at Veterans Affairs hospitals and some immigration issues.

That gave his supporters a boost. “I saw a poll yesterday, a tracking poll, that showed Sessions moving back up,” Shelby, who has hosted fundraisers in Washington for Sessions, said Thursday.

Advisers to rival campaigns suggest that there is an overlooked X Factor that could weigh Sessions down — the now five decades that he has been a public figure in Alabama. In 1981, President Reagan appointed him the state’s U.S. attorney, a post he held for 12 years.

In 1996, he won the Senate seat of Howell Heflin (D-Ala.), who played a key role in blocking Sessions’s nomination to be a federal judge. And in 2017, Trump appointed Sessions as his attorney general.

Some rivals think that Sessions, who has had only two public events this past week, has just grown stale with voters looking for a fresh face to shake up Washington.

Waiting in the wings, Jones is likely an underdog to any of the top three Republicans, unless the party fractures again as it did in 2017.

“As divisive and non-substantive as I’ve ever seen a primary. Totally non-substantive, it’s stunning,” Jones, who worked for Heflin in the early 1980s, said Thursday.

“Nothing amazes me anymore about Republican politics in Alabama,” he said.