If Republican challenger Walker wins the Senate seat, the chamber would stay in its current power-sharing agreement.

A 50-50 split has meant Democrats can't afford a single dissenter, leaving them with little breathing room in passing legislation. Senate Majority Leader Chuck Schumer has had to constantly corral his caucus, which spans from conservative Democrats like Sen. Joe Manchin, D-W.Va., all the way to progressive independents like Bernie Sanders, I-Vt. That dynamic would continue should Walker win the seat.

The split also slows the process for procedures like moving judicial nominees out of committee for a full vote. Republicans can block Biden nominees in the Judiciary Committee, forcing an additional vote on the Senate floor.

Florida Republican Sen. Rick Scott has alluded to that in pitching Walker to voters, saying he could help "block" the Democratic majoriry.-ABC News' Allison Pecorin

Polls closed at 7 p.m. ET in the Georgia Senate runoff race.

State officials said Tuesday they anticipate record turnout for a midterm runoff, with more than 1.4 million votes possibly cast on Election Day, on top of the nearly 1.9 million early votes.

After Georgia’s polls close at 7 p.m. ET, counties can begin reporting their vote totals, according to a Georgia secretary of state spokesperson. These numbers will most likely be early vote and absentees at first, which were able to start being tabulated at 7 a.m. on Tuesday

“Counties move through reporting Election Day totals as quickly as they can. Steady pace is typically the norm,” spokesperson Robert said.

Warnock, in his second consecutive runoff election in less than two years, has campaigned heavily in recent weeks on the theme of “character.”A reverend at Martin Luther King Jr.'s former church and Georgia’s first Black senator, Warnock also pitched himself to the battleground state's voters as a pragmatic, experienced leader.

“I’ll put my character up against Raphael Warnock any day,” Warnock told ABC News on Tuesday.

While Walker has waved off or simply ignored the controversies surrounding his campaign, some of the issues raised by them have become a part of his messaging to voters on mental health, his Christian faith and his path to "redemption."

Walker has also tried to paint Warnock as a “rubber stamp” for President Joe Biden, describing himself as a potential check on the administration, which is unpopular in Georgia.

Warnock, in response to Walker’s characterization of him, said he's worked with Republicans during his nearly two years in Washington.

"I am the 18th most bipartisan senator in the Senate. Period,” Warnock told ABC News Congressional Correspondent Rachel Scott on Tuesday. “Now I know that’s an inconvenient fact for Mr. Walker. We also know that he’s allergic to facts, even the facts about his own life.”

Walker acknowledged defeat at his election night party on Tuesday, admitting in a speech to supporters that media outlets had projected he lost to his Democratic opponent.

"But one of the things I said … when they called the race as they didn't know much, but one of the things I want to tell all you is you never stopped dreaming," he said.

"I'm not gonna make any excuses now, because we put up one heck of a fight."

The Trump-backed Walker, who has enjoyed an accomplished football and business career and is a father and two-time husband, said his run for the Senate was the "best thing I've ever done in my whole entire life."

He continued on to deliver largely hopeful remarks, encouraging his voters to keep casting their ballots and believe in the country.

"I don't want any of you to stop believing in America. I want you to believe in America and continue to believe in the Constitution and believe in our elected officials. Most of all, continue to pray for them because all the prayers you've given me, I felt those prayers," Walker said.

"I want to thank all my team as well [as] team Herschel because they put up with a lot, and I want to thank all my donors as well because you guys, without you, I couldn't have done what I've done."

Walker noted a "tough" journey for his wife -- a possible reference to some of the personal controversies that plagued his campaign, including some accusations he denied as political smears.

"I'm going to acknowledge my wife, Julie, because she's with me and she'd been through a tough time," he began.

"But I want to say that I want to thank all of you as well, because we've had a tough journey."

Walker ended by saying he was "never gonna stop fighting."

"Because I always am a winner and we all winner, so we all winners, and that's what I want to say, well, winners, and I want to say God to the good God."