The US state of Georgia is going to the polls for a second-round vote that will decide whether President-elect Joe Biden’s Democrats control the Senate.
Mr Biden’s party needs to win both seats in the state’s runoffs to gain full control of Congress – and with it the power to push forward his agenda.
The Republican Party of outgoing President Donald Trump needs only to win one in order to retain the Senate.
Mr Biden said Georgians could shape the US for years to come.
Meanwhile, Mr Trump told voters it was their “last chance to save the America” they loved.
Republicans Kelly Loeffler and David Perdue currently hold Georgia’s two Senate seats. Ms Loeffler is taking on Reverend Raphael Warnock and Mr Perdue is battling Jon Ossoff.
None of the candidates reached the 50% needed to win outright in the elections in November, forcing Tuesday’s runoffs under Georgia’s election rules. Voting began at 07:00 (12:00 GMT).
What’s at stake in Georgia?
The vote will decide the balance of power in the Senate.
The Republicans currently hold 52 of the 100 seats. If both Democrats win on Tuesday, the Senate will be evenly split, allowing incoming Democratic Vice-President Kamala Harris the tie-breaking vote.
This would be crucial for pushing through Mr Biden’s agenda, including on key issues such as healthcare and environmental regulations – policy areas with strong Republican opposition.
The Senate also has the power to approve or reject Mr Biden’s nominees for cabinet and judicial posts.
If Mr Ossoff and Mr Warnock both win, it would bring the White House, Senate and the House of Representatives under Democratic control for the first time since President Barack Obama’s election in 2008.
How will the vote proceed?
Voting should last about 12 hours, ending at 19:00 local time (midnight GMT), although all those still in line to vote at that time will be allowed to do so.
Democrats are hoping for a large turnout and have been buoyed by the fact that more than three million Georgians have already cast their ballots – nearly 40% of the state’s registered voters. Early voting was a key benefit for Joe Biden in the presidential election.
The Democrats will be looking to turn out supporters in major urban areas, particularly the suburbs of Atlanta. The issue of long lines of voters could be more of a problem for them.
For the Republicans, getting out voters on the day is even more crucial, and they will be looking to the stronghold of north Georgia, as well as rural areas and smaller towns.
Generally, results come in quickly but if these races are close, it could take days.
Mr Perdue nearly won first time out against Mr Ossoff in November, falling just short of the needed majority with 49.7%. The other seat had more candidates, with Democrat Mr Warnock recording 32.9% to Ms Loeffler’s 25.9%.
A Democrat has not won a Senate race in Georgia in 20 years but the party will be boosted by Mr Biden’s presidential election win over Mr Trump there. Mr Biden’s margin of victory was about 12,000 votes among five million cast.