Control of the US Senate - and with it the ability to block or advance President-elect Joe Biden's agenda - is on the line in a pair of runoff elections in Georgia on Tuesday after a dizzying campaign that shattered spending and early turnout records.
Incumbent Republican Senators David Perdue and Kelly Loeffler are trying to hold off Democratic challengers Jon Ossoff, a documentary filmmaker, and the Rev. Raphael Warnock, a pastor at a historic Black church in Atlanta, in a state Biden narrowly carried on Nov. 3.
The tumultuous contest's final days have been dominated by President Donald Trump's continued effort to subvert the election results. On Saturday, he pressured the state's Republican secretary of state to reverse Biden's statewide victory, claiming massive fraud contrary to evidence.
Illustrating the high stakes, both Trump and Biden campaigned in Georgia on Monday, Trump in the state's northwest and Biden in Atlanta.
The president called the Nov. 3 election "rigged" and falsely claimed he won the state on Monday, as he used his speech to air grievances about his defeat.
"There is no way we lost Georgia," Trump said, ticking off a long list of unfounded conspiracy theories about election fraud.
Biden's November win, the first for a Democratic presidential candidate in Georgia in nearly 30 years, was not confirmed for more than a week, and subsequent legal challenges from the Trump campaign pushed the state's final certification into December.
Some Republicans have expressed concern that Trump's baseless attacks may suppress turnout among his supporters. However, 50 Trump-supporting voters interviewed by Reuters last month said they planned to vote despite his claims.
A double Democratic win would split the Senate 50-50, with Vice President-elect Kamala Harris's tie-breaking vote giving Democrats control of the Senate. The party already holds a narrow majority in the House of Representatives.
A Republican-controlled Senate would likely block many of Biden's most ambitious policy goals in areas such as economic relief, climate change and policing.
"This is not an exaggeration: Georgia, the whole nation is looking to you," Biden told Monday's rally. "One state can chart the course, not just for the next four years, but for the next generation."
Polls are open until 7 p.m. local time (2400 GMT). Some 3 million ballots have already been cast in early in-person and mail voting, mirroring a trend seen in November due to the pandemic.
Barring an unexpectedly lopsided result, the winners are unlikely to be known on Tuesday, and perhaps for days, as state officials are not permitted to start tallying early votes until after the polls close.
Opinion surveys have shown both races are exceedingly tight. Nearly half a billon dollars in advertising has blanketed the state's airwaves, as dozens of independent political groups have descended on Georgia.
Democrats had been encouraged by the early vote, which included strong figures from Black voters, seen as crucial to their chances. But Republicans have historically turned out in higher numbers on Election Day.
Perdue and Loeffler have tried to strike a careful balancing act, offering support for Trump's rigged election claims while still arguing they represent the last barrier to an era of unrestrained liberalism in Washington.
At Monday's rally, the crowd broke into a "Fight for Trump" chant as soon as Trump mentioned Loeffler and Perdue by name.
On Monday, Loeffler said she would object to the certification of Biden's win when Congress meets on Wednesday to formally count the presidential vote, joining about a dozen other Republican senators. Perdue, whose term technically ended on Sunday, has voiced support for the extraordinary move, which has virtually no chance of succeeding.
The campaign has seen bitter attacks, with Loeffler and Perdue characterizing the Democrats as "radical socialists" and Ossoff and Warnock calling the incumbents deeply corrupt. But all four candidates agree on one thing: the election carries enormous consequences.
Loeffler said the country's "way of life" was on the ballot, while Warnock told supporters Tuesday is a "defining moment in American history."
The runoff elections, a quirk of state law, became necessary when no candidate in either race earned 50% in November.