WASHINGTON — Tens of millions of Americans have already made their way to the ballot box as early voting is underway in a midterm election that will determine control of the House and the Senate, possibly flipping one or both from Republicans to Democrats. As of Tuesday afternoon, more than 34 million people have either gone to the polls to cast a ballot or have mailed in their vote, and the current tally is on track to surpass early voting in the 2022 midterm elections, said Michael McDonald, a professor of political science at University of Florida who runs the UF Election Lab that tracks early voting. With one week until Election Day on Nov. 3, McDonald said he’s not sure if voters will surpass record-breaking early voting of 2018, but it’s clear that the surge in early voting will eclipse turnout in the 2022 midterm elections, where nearly 46 million Americans voted early, according to the UF Election Lab . “Right now, the data that I can see, it looks like we’re running at least even to the 2018 election. If the voting continues through Election Day, we would be somewhere around that number,” he said. “That’s a high water benchmark,” McDonald said, adding that the 2018 election was the highest turnout for a midterm election since 1914. Motivations for the surge Some states are reporting heavier voter turnout. Twenty-seven states record party affiliation, and of the roughly 16 million early voters in those states, 45% are Democrats, and about 31% are Republicans, with 24% unaffiliated with either party, according to the UF Election Lab. South Dakota advance voting From South Dakota Searchlight The number of advance ballots received in South Dakota for the Nov. 3 election stood at 49,438 as of Oct. 23, according to the Secretary of State’s Office , which reports the numbers weekly. That’s ahead of the pace for the 2022 midterm election , when 34,794 advance ballots had been cast through the fifth week of advance voting. Advance voting options in South Dakota include voting in person at a county office, or voting by mail or authorized messenger. McDonald said he can’t tell from the data the motivation behind a surge in early voting, but he has two ideas. The first is a post-COVID 19  explanation, where voters are less likely to partake in mail-in-ballots, so “we’re sort of reverting back to a normal election.” “The other is the potential that (President Donald) Trump’s potential threats with trying to monkey around with the U.S. Postal Service, has made some people decide that they don’t want to vote by mail and vote in person instead,” he said. The U.S. Supreme Court in September kept in place a lower court’s order blocking Trump’s embattled plan to place new restrictions on mail ballots for this year’s midterm elections. The GOP is vying to maintain its narrow majority in the House and Senate, though Democrats remain heavily favored to win back the majority in the House, and Senate races continue to move in the party’s favor, according to elections forecasters. The party of the president historically loses seats in the midterm elections. Trump is also facing anemic approval ratings amid the war in Iran and its impact driving up gas prices. The Cook Political Report with Amy Walter shifted 19 House races in the direction of Democrats on Oct. 23. The elections forecaster lists 17 races as toss-ups , with Republicans defending 12. In the Senate, the Cook Political Report identified seven toss-up races across the country, including in Alaska, Iowa, Kansas, Maine, Michigan, Ohio and Texas. Early voting in the battlegrounds As early voting continues in key battleground states, Republicans are aiming to hold on to their majority in the upper chamber. In Alaska, as of Monday, more than 46,000 people have voted already , according to the UF Election Lab . Former House Democratic Rep. Mary Peltola is seeking to unseat incumbent GOP Sen. Dan S. Sullivan. Voter Guide: 2026 general election In Iowa , as of Tuesday, nearly 307,000 people have cast their vote early, as Democratic state legislator Josh Turek and U.S. House Republican lawmaker Ashley Hinson compete in a toss-up race for the U.S. Senate seat. GOP incumbents Susan Collins of Maine and Roger Marshall of Kansas are also trying to keep their Senate seats in tough challenges from Democrats. In Maine, more than 196,000 people have voted, according to Monday data from the UF Election Lab. And in Kansas, more than 245,000 people have voted as of Tuesday, according to the UF Election Lab . More than 1.3 million people have already voted early in Michigan as of Tuesday, according to the UF Election Lab . The Wolverine State is home to a highly competitive Senate race in an open seat between Republican Mike Rogers and Democrat Abdul El-Sayed that the Cook Political Report has declared a toss-up. In Ohio, as of Tuesday, nearly 1.2 million people have voted early as well, per the tracker . A tight Senate race also listed as a toss-up by the Cook Political Report features Ohio GOP Sen. Jon Husted and Democratic candidate and former Sen. Sherrod Brown. In the Lone Star State, more than 5 million people have cast their ballots as of Tuesday, according to the UF Election Lab . Texas Attorney General Ken Paxton, a Republican, and James Talarico, a Democrat, are battling it out in a race dubbed a toss-up by the Cook Political Report. Trump was campaigning in Texas on Tuesday. Big turnout in some states As early voting takes shape across the country , some states are seeing sweeping turnout figures during the beginning days of early voting compared with earlier elections. In Tennessee, midterm early voter turnout stood 57% higher compared with the 2022 midterms in the Volunteer State during the first eight days, according to a Monday report from the Tennessee Lookout . Meanwhile, North Carolina is witnessing an eagerness among unaffiliated voters, who cast 34% of ballots in the first five days of early voting in the Tar Heel State, NC Newsline reported. The Louisiana Illuminator reported that Black voters comprised a larger share of participants on the first day of early voting in the Pelican State compared with nearly every other election over the past 18 years.