Midterm elections live updates: Voters heading to polls today for high-stakes midterms

After months of candidates campaigning, Tuesday marks the midterm elections.

The balance of power in both the U.S. Senate and the U.S. House of Representatives is up for grabs on Tuesday as Republicans and Democrats vie for seats in key races across the country. There are also significant races for governor around the country.

More than 57 million early votes have been cast nationwide as of Monday afternoon, according to the Election Lab at the University of Florida. That number is set to outpace the more than 58 million total number of early votes cast in 2022.

-ABC News' Oren Oppenheim

An analysis of Federal Election Commission data by campaign finance tracker, OpenSecrets projects that spending on the 2025-2026 election cycle will reach about $12 billion -- meaning that, at the federal level, this cycle is slated to be the most expensive midterm election on record.

An analysis by AdImpact that incorporated gubernatorial elections found it to be the most expensive cycle on record, surpassing even the 2023-2024 general election cycle.

Advertising spending across House, Senate and gubernatorial races this cycle cost about $7.1 billion, according to an analysis by the Wesleyan Media Project. About $1.4 billion of that ad spending occurred late in the cycle, between Oct. 12 and Oct. 25.

-ABC News' Will Lennon