Millions of US citizens have already voted in the hotly contested 2018 midterm elections ahead of polls opening on Tuesday.
Aside from absentee voting, which allows residents to vote when they are traveling outside the state or country, 37 states and the District of Columbia allow some form of early voting.
With the 2018 midterms taking place amid a polarised political climate, experts say it is no surprise early voting will surpass 2014 midterm election levels.
“It looks like we’ll wind up with approximately 40 million mail and in-person early voting this year,” tweeted University of Florida Professor Michael McDonald, who researches early voting.
Mr McDonald added that 27 states and Washington DC have already surpassed their 2014 midterm early voting totals.
The apparent uptick in early voting has the potential to impact races in key states. Under the previous administration of President Barack Obama, Democrats lost control of the House in 2011 and then the Senate in 2015. The party cited a low turnout among their supporters as an issue.
In this year's ballot, Democratic candidates are already saying that the high turnout could secure them key seats. Over the weekend, US political website The Hill reported that nearly 40 per cent of registered voters in Texas had already cast a ballot, more than in previous midterm elections and several previous presidential elections.
"If North Texas continues to turn out in the record numbers that we've seen, shattering every midterm total for as long as we've been looking at them, in some cases rivalling presidential voter turnout, then we're going to win this race," Democratic candidate Beto O'Rourke said on Friday. Mr O'Rourke is facing off against Ted Cruz, a longterm Senator and former candidate for Republican presidential nomination.
Rules vary within the states allowing for early voting. In Ohio, for example, in-person voting can begin 35 days before an election, whereas in Florida, citizens can vote 10 days before.
As for Colorado, Washington and Oregon, voting takes place by mail, adding various options for those choosing to submit early ballots.
Thirteen states, including New York in Pennsylvania do not allow voting ahead of election day.
In the US, election days are not considered national holidays, prompting some states to allow multiple options for voters.