Control of the Senate all comes down to the two runoff contests in Georgia on Tuesday, bringing in some big hitters from both parties.
"Changing the balance in the United States Senate, which is what this election will do, will make all the difference," said Vice President-elect Kamala Harris. "And we're going to keep fighting to hold the line in the United States Senate," said Vice President Mike Pence.
Excluding the two seats up for grabs in Georgia, the current party split in the upper chamber looks like this: 50 Republicans and 46 Democrats, plus the two independents who caucus with them.
If GOP Sens. David Perdue and Kelly Loeffler both win on Tuesday, Republicans will have a 52-48 majority, with Sen. Mitch McConnell remaining as majority leader.
If both the Democrats win — Raphael Warnock and Jon Ossoff — then the Senate will be split 50-50. With President Trump still in the White House, that makes Vice President Mike Pence the tiebreaker and the Republicans would keep the majority until Jan. 20. Once President-elect Joe Biden is sworn in, Vice President-elect Kamala Harris takes over the tie-breaker role, which would give Democrats the majority for the first time since 2015.
If the seats split one and one, then Republicans will keep control with just a one-vote margin over the Democrats.