US President Donald Trump and president-elect Joe Biden will head to Georgia in the coming days to campaign before a vote that will decide which party controls the Senate for the next two years. Kamala Harris, the vice president-elect, is campaigning for Democrats in Savannah on Sunday. The next day, Mr Biden will appear in the state capital Atlanta and Mr Trump will lead a rally for the Republican candidates in Dalton. In a tweet on Wednesday, Ms Harris urged Georgians to “get out and vote” for the two Democratic candidates in an unusual double run-off, saying it is “within our power to change the course of our country’s history”. On January 5, Georgia voters will choose between Republican senator David Perdue and his Democratic challenger Jon Ossoff, and Republican senator Kelly Loeffler and Democrat Raphael Warnock. None of the candidates got more than 50 per cent in the November 3 general election, leading to a run-off that has garnered national attention thanks to a knife-edge balance of power in the 100-seat US Senate. If the Democrats win both Georgia races, the Senate would be split 50-50 with Republicans, giving the tiebreaking vote to Mr Biden’s deputy in his incoming administration, Ms Harris, and control of both chambers to the Democrats. A double win for Democrats in Georgia would make it easier for Mr Biden to pass laws on immigration, healthcare and other parts of his legislative agenda once he takes control of the White House on January 20. Millions of Georgians have already cast ballots in the run-offs and record-breaking sums of hundreds of millions of dollars have been spent on campaigns. Polling in both races is tight, meaning the chances of a double-Democrat win are slim. In the November 3 general election, the Georgia results were so close that it took 10 days for television networks to project Mr Biden had won the state. The results of the senate run-off votes could be similarly slow, analysts say. <em>The National</em> takes a look at the four candidates: <strong>David Perdue</strong>, 71, is the former chief executive of Reebok athletic brand and a retail chain and one of the wealthiest congressmen. He joined the Senate in 2014 with a desire to "shake up Washington" and is one of Mr Trump's "closest allies", he says on his website. <strong>Jon Ossoff</strong>, 33, is a documentary filmmaker and investigative journalist who has never held public office. He promises to work to improve healthcare, increase clean energy production and roll back the damage of the Trump era. <strong>Kelly Loeffler</strong>, 50, was appointed to her Senate seat last year to serve out the unfinished term of former senator Johnny Isakson. She describes herself as a conservative businesswoman, a political outsider and a Trump loyalist who will fight "radical socialism". <strong>Raphael Warnock</strong>, 51, is the pastor of a well-known African-American church in Atlanta where Martin Luther King used to preach. He says he will work to improve health care and fight for struggling Georgia families.