All eyes turn to Atlanta, Georgia on Tuesday when Democratic candidate Jon Ossoff takes on Karen Handel, the Republican former secretary of state for Georgia, for the congressional seat vacated by secretary for health and human services Tom Price.
The election follows a first-round vote last month that saw 30-year-old Ossoff come within touching distance of winning the traditionally Republican seat. The failure by any candidate to secure more than 50 per cent of the vote in the first round pushed the battle to a run-off.
The election is being closely watched by both parties as a signal of what may lie ahead in next year’s mid-term elections, when Democrats hope to win back control of the House of Representatives.
The sixth congressional district of Atlanta was expected to be an easy win for Republicans – Newt Gingrich, the former house speaker, held the seat for 20 years. But Mr Ossoff, a relative political unknown, garnered 48 per cent of the vote in the first round of elections in May.
Republican territory
While the seat is in traditional Republican territory, US president Donald Trump did not fare well there in last year's presidential election, winning the district by just 1.5 percentage points, compared to Mitt Romney's 23-point victory in 2012.
Opinion polls on the eve of today’s vote showed Mr Ossoff slightly ahead, though analysts warned that early voting in the district makes it notoriously difficult to predict the outcome.
The election has attracted huge donations, particularly from Democrats, who are hoping for a victory that could boost momentum ahead of next year’s elections.
Republicans have hit back with a massive ad campaign, including one controversial ad which appears to link Mr Ossoff with last week's shooting that left Republican congressman Steve Scalise wounded. The ad, which blames "unhinged leftists" on the attack, was condemned by both campaigns on Monday. House majority leader Kevin McCarthy became the latest senior Republican to campaign on behalf of Ms Handel on Monday, as Republicans moved to clinch last-minute votes in the final hours before voting.
Political gerrymandering
Meanwhile, in a highly significant move, the US Supreme Court on Monday announced that it would consider a case on political gerrymandering, a highly sensitive issue in US politics.
The court will consider in the autumn whether the partisan redrawing of electoral districts may be unconstitutional. A number of State legislatures have redrawn electoral boundaries in recent years, often to benefit their own party.
President Trump was at the White House on Monday where he hosted some of the world's most senior technology executives, including the chief executive of Apple, Tim Cook, and Google boss Eric Schmidt.
Mr Trump has been trying to focus attention away from the Russia scandal that has engulfed his administration and towards the policy initiatives he believes he and his administration are introducing.
“The MAKE AMERICA GREAT AGAIN agenda is doing very well despite the distraction of the Witch Hunt. Many new jobs, high business enthusiasm,” the president tweeted on Sunday.
Not under investigation
A member of Mr Trump's legal team has insisted the president was not under investigation for obstruction of justice, despite Mr Trump stating on Twitter that he was being investigated for firing FBI chief James Comey.
"The president is not a subject or target of an investigation," Jay Sekulow, one of Mr Trump's personal lawyers, said on Sunday. "That tweet was in response to a Washington Post story that ran with five unnamed sources, without identifying the agencies they represented, saying that the special counsel has broadened out his investigation to include the president."
