Jeff Sessions' bid to reclaim an Alabama Senate seat for Republicans amounts to a grudge match with his former boss, President Donald Trump, whose popularity has been dented by the U.S. recession and a surge in coronavirus cases across the South.

Trump cast Sessions aside as U.S. attorney general two years ago in anger over his recusal from the Russia investigation and hasn't forgotten. He may get a final bit of revenge by backing former Auburn University football coach Tommy Tuberville, who's favored in Tuesday's primary runoff. "This is Trump's final twist of the knife at the back of Sessions' head," said Jessica Taylor, Senate editor for the nonpartisan Cook Political Report.

Despite Sessions' history in Alabama as a U.S. attorney, state attorney general and three-term U.S. senator, Tuberville holds a significant lead in polls after narrowly coming out on top in the first round of voting on March 3.

The outcome will do more than settle an intraparty squabble in a heavily Republican state. The winner on Tuesday will have a key role in the GOP effort to hold on to its majority in the Senate after the November general election. With at least five Republican senators facing threat of defeat, the GOP is looking to topple Alabama's other senator, Doug Jones, the most vulnerable Democrat on the ballot.

Jones won a narrow victory over Roy Moore, a controversial Republican candidate who had been endorsed by Trump, in a 2017 special election to fill the seat Sessions had vacated to join Trump's administration.

Sessions has assailed Tuberville on the campaign trail over his stance on immigration, his connection to a fraudulent hedge fund, lack of roots in Alabama and for ducking debates. Tuberville touts his status as a political outsider, his success as a coach in college football's top tier and, particularly, the Trump endorsement in a state where the president won 62% of the vote in 2016. He's accused Sessions of having "cut and run" on Trump.

The former senator's quest to regain his old job has a Shakespearean quality to it. Sessions was Trump's earliest and by far his most fervent Senate backer in 2016. He campaigned for Trump and gave up a safe Senate seat to become his attorney general. Sessions' longtime aide Stephen Miller is a top adviser for Trump.

That changed in 2017 when then-Attorney General Sessions complied with a Department of Justice regulation that he recuse himself from the investigation into the campaign in which he played a key role.

Trump decried the recusal, questioning his loyalty. "Jeff Sessions was a disaster," Trump told Fox's Sean Hannity.

Tuberville has also faced controversies. The New York Times wrote about his involvement in a fraudulent hedge fund — an associate was charged with the fraud and Tuberville was sued by investors who later settled with the former coach, the Times reported.

Sessions, 73, has faced the political wilderness before, when he was rejected for a U.S. District Court judgeship in 1986 over disputed charges about his actions and comments on race. He ultimately won a Senate seat and a place on the Judiciary Committee — the very panel that had turned him away. By 2014, he was seen as so unbeatable no one challenged his most recent re-election to the Senate.

Winning Tuesday would bring him back from the political dead for a second time.