This January, two outstanding Senate races in one state, Georgia, will decide control of the U.S. Senate, which will have a big impact on how much President-elect Joe Biden can get done in his first two years in office. Here’s everything you need to know about the highest-stakes political races in the country.

Why are these two runoffs in Georgia happening?

Because no candidate got more that 50 percent of the vote in November. When that happens, Georgia election law says the top two vote-getters must go to a runoff.

Georgia is also in a unique position by having both Senate seats up right now. One is a regular election, as Sen. David Perdue (R) finishes his first six-year term and runs for reelection. The other is a special election after a Republican senator retired last year. Georgia’s governor appointed Sen. Kelly Loeffler (R) to the seat, and now she’s running in her first election for a full term.

Loeffler’s race was crowded, so it was expected to go to a runoff, because there were too many candidates for one to consolidate 50 percent or more of the vote. That Perdue’s race is going to a runoff is more of a surprise.

[Listen to a one-hour episode of Post Reports examining the Georgia runoff]

When are the runoffs?

They will both be held Jan. 5. Any registered Georgia voter, regardless of whether they voted in November, can vote in this election. The pandemic is still shaping how Georgians will vote. Early in-person voting started Dec. 14, and Georgians can vote by mail. All this means that, just like the general election, it could take several days for election officials to tally results.

Sens. Kelly Loeffler and David Perdue talk offstage before a rally with President Trump on Dec. 5 in Valdosta, Ga. (Jabin Botsford/The Washington Post)Sens. Kelly Loeffler and David Perdue talk offstage before a rally with President Trump on Dec. 5 in Valdosta, Ga. (Jabin Botsford/The Washington Post) The Democratic Senate candidates, the Rev. Raphael Warnock, left, and Jon Ossoff, speak at a campaign event on Dec. 14 in Atlanta. (Megan Varner/Getty Images)The Democratic Senate candidates, the Rev. Raphael Warnock, left, and Jon Ossoff, speak at a campaign event on Dec. 14 in Atlanta. (Megan Varner/Getty Images)

LEFT: Sens. Kelly Loeffler and David Perdue talk offstage before a rally with President Trump on Dec. 5 in Valdosta, Ga. (Jabin Botsford/The Washington Post) RIGHT: The Democratic Senate candidates, the Rev. Raphael Warnock, left, and Jon Ossoff, speak at a campaign event on Dec. 14 in Atlanta. (Megan Varner/Getty Images)

Who is running against whom?

Sen. David Perdue vs. Jon Ossoff

Perdue, 71, is a wealthy former businessman.

Ossoff, 33, is a documentary filmmaker who was the Democratic candidate for a high-profile special congressional election in 2017 that he ultimately lost. He has never served in public office.

Sen. Kelly Loeffler vs. Raphael Warnock

Loeffler, 50, was appointed to this Senate seat last year and has never won a statewide election. Her husband is chief executive of the New York Stock Exchange’s parent company, and she is one of the wealthiest members of Congress. Like Perdue, she has positioned herself as a Trump loyalist. Both have refused to acknowledge President Trump lost the election. They’ve questioned the integrity of the election in their own state and use terms like “radical” and “socialist” to attack their Democratic opponents.

Warnock, 51, is the pastor of a well-known Black church in Atlanta where the Rev. Martin Luther King Jr. used to preach, and he’s getting lots of attention from both sides, animating the Democratic base and as the target of Republicans trying to cast him and his party as too extreme. It’s put a spotlight on Black religious Americans, making some of them feel like the target of sometimes-racist attacks.

Both Democrats have positioned themselves as generally in line with Biden and his policies, especially on health care and fighting the coronavirus. They have tried to wield the Republican candidates’ stock trades and loyalty to Trump as weapons.

How these races will determine control of the Senate

Democrats had a chance in November to retake the Senate, but Republicans held the line in key races. Now, Democrats need both these Georgia Senate runoffs to get to a 50-50 tie in the Senate. If they can do that, they’ll effectively have the majority, because Vice President-elect Kamala D. Harris can cast a tie-breaking vote. That would hand over the reins of the Senate to Minority Leader Charles E. Schumer (D-N.Y.) and put current Majority Leader Mitch McConnell (R-Ky.) back in the minority.

But the minority still wields significant power in the Senate. Any senator can block legislation by filibustering it, requiring 60 votes to overcome it. At their best, Democrats will have 51 votes with Harris. If they lose one or both Georgia Senate races, Republicans will keep the majority.

Theresa Cross canvasses in immigrant neighborhoods in Clarkson, Ga., on Dec. 12. (Melina Mara/The Washington Post)Theresa Cross canvasses in immigrant neighborhoods in Clarkson, Ga., on Dec. 12. (Melina Mara/The Washington Post)

Who is favored to win?

Both are going to be extremely close races.

The Republicans have at least two advantages: Georgia is a Republican-leaning state, and Republican Senate candidates got more votes than Democratic candidates in November. Perdue got about 88,000 more votes than Ossoff, even after Ossoff received the most votes of any statewide Democratic candidate in Georgia, ever.

“Georgia is a state that wants Republican senators,” said one Republican strategist who works on Senate races in Georgia and spoke on the condition of anonymity to be candid, after the runoff was announced. “That’s the message we got here. We’re just going to have to work a little harder to make sure that happens.”

But for the first time since 1992, Georgia voted for a Democrat for president, as independent and Republican-leaning voters in the suburbs turned against Trump. Democrats harnessed those demographic changes to perform remarkably well in the suburbs and outer suburbs. They had record turnout in counties outside Atlanta, and they managed to get a lot of people to successfully vote by mail.

“There is a demographic change happening in Georgia that is only accelerating every year,” said a Democratic strategist who has worked on Senate races in Georgia and spoke on the condition of anonymity to be candid. “The state is diversifying and urbanizing at an incredible clip.”

Both parties are approaching this January election differently from November’s. No longer are they trying to persuade undecided voters. The party that wins both these seats will have done so because they successfully turned out more of their base.

Two weeks before the election, an astonishing 1.4 million people have already voted, which is close to how many voted two weeks early in Georgia in the general elections in November. This suggests a very engaged electorate. And it looks like Democrats have a slight lead in terms of who’s turning out already to vote, according to a Washington Post analysis.

But Republicans are catching up to Democrats with mail voting. There’s evidence that older Georgians are requesting ballots more so than younger voters, which heartens Republicans, especially as some Trump allies urge a boycott of the election over baseless fraud claims in the state.

[How votes shifted in the six political states of Georgia and what it could mean for the runoffs]

Perdue and Loeffler join Trump onstage at a rally on Dec. 5 in Valdosta, Ga. (Jabin Botsford/The Washington Post)Perdue and Loeffler join Trump onstage at a rally on Dec. 5 in Valdosta, Ga. (Jabin Botsford/The Washington Post)

Will Trump’s claims of election fraud in Georgia matter?

Republicans have to navigate some tricky base politics, though. When this election happens, Trump will be in his final days in office. Republicans would love to argue that their seats are the last lines of defense against an entirely Democratic Washington. But they can’t — at least not publicly — because Trump hasn’t conceded the race. So instead, Perdue and Loeffler are forced to try to balance the reality that Trump lost, which they’ve acknowledged in private calls, with their base’s insistence that Trump really won were it not for a somehow fraudulent election.

“The future of the country is on the line right here,” Loeffler said at a recent rally. “We are the firewall.”

That raises another concern for these Republicans: whether Trump’s false claims that the election — particularly in Georgia — was rigged will turn off some Republicans from voting. The issue has divided the Georgia Republican Party, and turned Perdue and Loeffler against the governor and secretary of state. They even demanded that Secretary of State Brad Raffensperger (R) step down despite the fact that three recounts have confirmed he presided over a free, fair and accurate election in Georgia. A week before the election, Trump called for Georgia’s Republican governor to resign over baseless fraud claims the president is making.

Some of Trump’s allies in Georgia have been urging voters to boycott the runoffs because he lost the state. Here’s a photo from one such rally.

Supporters listen to speakers during a “Stop the Steal” rally in Alpharetta, Ga., on Dec. 2. (Ben Gray/Atlanta Journal-Constitution/AP)Supporters listen to speakers during a “Stop the Steal” rally in Alpharetta, Ga., on Dec. 2. (Ben Gray/Atlanta Journal-Constitution/AP)

It’s hard to tell how many people might actually boycott the election. When top Republicans campaign in Georgia, they are often met with chants to “Stop the steal!” and crowds more animated by Trump’s fraudulent claims he won rather than Loeffler and Perdue. A mid-December Fox News poll found that just 69 percent of Georgia Republicans said the presidential election made them more likely to vote in the runoff, compared with 84 percent of Democrats.

Trump went to Georgia and tried to bridge these competing realities. He falsely claimed the state’s elections apparatus and officials can’t be trusted, and urged his base to vote in the January runoffs anyway. That may have been the opening some Republican voters needed, though, to feel like they can and should vote in January even as they think the election was rigged, reports The Washington Post’s Cleve R. Wootson Jr.

“We can still vote, and we can still get these two senatorial candidates reelected and still be mad about what’s happening with [the] president,” said Rep. Earl L. “Buddy” Carter (R-Ga.).

Loeffler and Perdue are also focused on rallying their bases by accusing Warnock and Ossoff of being too liberal or, in Warnock’s case, too radical, even though they both Democrats say they support moderate positions in line with Biden.

Another open question for Republicans is whether normally reliable GOP voters who voted against Trump in November and helped Biden win the state will come back home to the Republican Party and vote or Perdue and Loeffler in January. Or they may skip the race entirely, which could hurt Republican turnout.

Biggest moments of the races so far

Trump softens his tone somewhat on Georgia

Under pressure from Republicans worried about how his fraud claims were dividing the party and disengaging voters in the state, Trump held a rally in Georgia, where he both expanded on those fraud claims but urged Republicans to vote, as a way to get back at Democrats. “The answer to the Democratic fraud is not to stay at home,” he said. “That’s what Nancy Pelosi and Chuck Schumer want you to do, to stay at home.”

Warnock, left, and Ossoff are joined by Biden during a Dec. 15 rally in Atlanta. (Joshua Lott/The Washington Post)Warnock, left, and Ossoff are joined by Biden during a Dec. 15 rally in Atlanta. (Joshua Lott/The Washington Post)

Biden campaigns in Georgia

A day after he won the electoral college vote, Biden went to Atlanta to campaign alongside Ossoff and Warnock. His visit underscored how Democrats need to, in the words of one strategist, set up the largest get-out-the-vote operation in Georgia’s history to win.

“Y’all did something extraordinary in November,” Biden said. “You voted in record numbers. You voted to improve the lives of every Georgian, and you voted as if your life depended on it. Well, guess what? Now you’re going to have to do it again come January 5th. You got to vote in record numbers again.”

Vice president-elect Kamala D. Harris has also campaigned for Democrats in Georgia.

A Cobb County election worker holds up a sign signaling that she needs help with determining a vote during a hand recount for the presidential election in Marietta, Ga., on Nov. 13. (Kevin D. Liles for The Washington Post)A Cobb County election worker holds up a sign signaling that she needs help with determining a vote during a hand recount for the presidential election in Marietta, Ga., on Nov. 13. (Kevin D. Liles for The Washington Post)

The many recounts

For the first half of the Senate runoff campaigns, Georgia was still litigating its November election results, as Republican election officials defended the election from Trump and his allies’ false claims of election fraud. Raffensperger ordered three recounts, including one done by hand, which is the most arduous and accurate way of counting ballots.

A day after Biden won the electoral college, Raffensperger announced he’d acquiesce to one of Trump’s other demands. Election officials will review whether, in one of Georgia’s largest counties, poll workers approved mailed ballots only after diligently matching voters’ signatures on the outside of the envelope with the signature the government had on file. Signature matching is a widely accepted security practice to ensure voters who mail ballots are who they say they are.

“Now that the signature matching has been attacked again and again with no evidence, I feel we need to take steps to restore confidence in our elections,” Raffensperger said.

The candidates’ controversies so far

Perdue’s stock trades

This spring, the Justice Department looked at whether Loeffler illegally traded stock to profit off a classified coronavirus briefing. Investigators dropped the case. Now that the national political reporting apparatus is focused on Georgia, there has been new reporting that Perdue, too, was also under Justice Department investigation for stock trades that paid off handsomely at the start of the pandemic, and there has been a steady drip of other news about his stock trades. That inquiry has closed, and Perdue has denied wrongdoing. Democrats have, of course, hammered both Republicans as corrupt.

Loeffler’s photo with a KKK leader

At a recent campaign event, Loeffler posed side by side with a former, well-known Ku Klux Klan leader. As the photo made national news, Loeffler’s campaign said she didn’t know that was him.

GOP attacks Warnock as radical

Republicans view Warnock, the only Black candidate in the race, as both a target and a threat, reports Wootson. Their game plan is to make him seem as radical as possible, including by tying him to former Obama pastor Jeremiah Wright’s most controversial comments, which fact-checkers have said is misleading. Loeffler accused Warnock of inviting former Cuban dictator Fidel Castro to speak at a church where he worked in the ’90s. There’s no evidence Warnock played a role in that invitation; he was the church’s youth pastor at the time.

Warnock has tried to brush all this off as Republicans using scare tactics. To make himself seem much less threatening, he’s run not one but two ads with him and a puppy. He also sarcastically joked in another that he shouldn’t be elected because he eats pizza with a fork and a knife.

Where can I find results?

We’ll be tracking them at The Washington Post.