By Nathan Layne
ATLANTA (Reuters) - A Tuesday runoff election in Georgia between Democratic U.S. Senator Raphael Warnock and Republican former football star Herschel Walker will determine whether President Joe Biden's party can expand its razor-thin majority in the Senate.
The race will also serve as a final test of Donald Trump's clout with midterm election voters as he seeks the Republican nomination to challenge Biden in 2024. The former president had a mixed record in his most competitive endorsements for Congress, including Walker.
Walker's campaign has been plagued by a variety of allegations, including claims he has called untrue by former girlfriends who said he encouraged them to get abortions, although he has campaigned for the procedure to be outlawed.
The race, which went to a runoff after neither candidate secured 50% of the vote in the Nov. 8 first round, has become the most expensive of the 2022 U.S. midterm election season, with more than $400 million spent so far. Campaign finance records show Warnock with a clear advantage in fundraising.
A victory by Warnock would give Democrats a 51-seat majority in the 100-seat Senate, which would make it slightly easier to advance Biden's nominees for judicial and administrative posts. Most legislation would still require Republican support.
Polls close at 7 p.m. Eastern time (0000 Wednesday GMT), and at least 1.87 million people cast their votes before Election Day, equal to 47% of the Nov. 8 turnout.
Analysts say those votes likely tilted Democratic, which will require strong Election Day turnout by Walker's Republican supporters. Opinion polls have shown a narrow lead for Warnock.
"We need you to show up. If you haven't already voted you need to vote on Election Day," Warnock said at a Monday rally at the Georgia Institute of Technology.
Warnock is the pastor of the historic Atlanta church where slain U.S. civil rights icon Reverend Martin Luther King Jr. once preached. Both Warnock and Walker are Black.
Walker has accused Warnock of backing policies that fuel inflation and has campaigned against transgender women competing in women's sports.
Walker on Monday spent his time in conservative areas of northern Georgia.
"I feel pretty good. We can win this thing," Walker said as he greeted well-wishers at a store in Calhoun. He did not take substantive questions from the press.
Gary Wilson, 69, who owns a heating and air business, said he believed Walker was a decent person in addition to a sporting great.
"Through the years everybody has looked up to Herschel for what he had done with the football team. But he's a good person," he said.
Along with the abortion claims, former girlfriends have also accused Walker of domestic abuse. He has also faced allegations that he maintains his primary residence in Texas, not Georgia.
Walker has denied the charges, but they may have discouraged some Republican voters. Warnock edged him 49.44% to 48.49% in November, even as Republican Governor Brian Kemp and other statewide Republican candidates easily won re-election.
Republicans won a narrow majority in the U.S. House of Representatives in the Nov. 8 election, but fell short of the "red wave" that some had forecast. The party also failed to capture a Senate majority.
This is the third Senate runoff in two years in the closely divided state - and the second for Warnock, who first won the seat in a runoff in January 2021.
Kemp has been campaigning for Walker and Trump held a tele-rally for Walker on Monday night, but did not campaign for him in person.
Warnock, meanwhile, drew former President Barack Obama to a rally last week but Biden has not been to Georgia to campaign for Warnock.
(Reporting by Nathan Layne, additional reporting by Steve Holland, writing by Andy Sullivan; Editing by Scott Malone and Rosalba O'Brien)