The Republican Party has pushed to enact new curbs on mail-in voting, which surged in the 2020 presidential election and fueled former President Donald Trump's false claims that he was robbed of victory by widespread voter fraud.

Citing security concerns, 18 states passed new legal limits on mail-in voting in the months after the election, from extra identification requirements to shortening the window in which mail ballots can be requested or cast.

Mail-in voting is unlikely to be used as heavily in November's congressional election as it was in 2020 during the height of the COVID-19 pandemic, but voting rights advocates warn the new restrictions could disenfranchise voters.

THE 2020 MAIL-IN VOTING DEBATE

As the COVID-19 pandemic surged across the country in 2020, prompting Americans to avoid public spaces, many states expanded mail-in voting to accommodate the increasing demand. Trump attacked the method as insecure, tweeting in May 2020 that mail-in ballots would "lead to massive corruption and fraud."

It took four days for media outlets to declare President Joe Biden the winner, due in part to some states continuing to accept mail-in ballots for days after Election Day, so long as they were postmarked by that date.

Citing that delay as proof that vote tampering was afoot, Trump falsely declared victory hours after Election Day, claiming the millions of mail-in votes still being counted were fraudulent.

WHO DOES MAIL-IN VOTING BENEFIT?

Democrats represented a far greater share of mail-in voters in the 2020 presidential election than Republicans, thanks in part to Trump's insistence to his base that it was insecure.

But multiple studies have found that higher mail-in voting participation generally does not appear to turn out more Democratic voters than Republican ones, nor does it improve the odds of a Democratic candidate winning an election.

In Texas, for instance, the rise in Democratic voters who voted by mail in the 2020 election was offset by the smaller portion of Democrats who voted in person, according to a study in Science magazine published last December.

Although all scientifically sound studies found virtually no fraud in the 2020 election, mail-in voting does carry increased risks for vote tampering, simply because the ballot has to travel a longer distance between the voter and the election office, according to University of Chicago public policy professor Anthony Fowler.

The most secure method for avoiding election interference, according to Fowler, is voting in person on paper ballots that are kept in a lockbox until being counted. But there are "trade-offs," he said, because it is also important to enfranchise voters who can't easily get to polling places, such as people who lack reliable transportation, the elderly or infirm, and residents of rural areas.

CHANGES TO MAIL-IN VOTING LAWS

In the name of improving election security, 18 states, mostly with Republican-controlled legislatures, passed laws after the 2020 election that curtailed access to mail-in voting, while 22 states expanded it, according to the Brennan Center for Justice and Voting Rights Lab.

Some legislation contained both expansions and restrictions, such as an Indiana law that limited the use of boxes where voters could drop their absentee ballots, but also made it easier to return a ballot on behalf of another voter and to fix mistakes on absentee ballots.

The most dramatic fallout from new mail-in voting restrictions has been in Texas. A law passed in 2021 requires election workers to automatically reject mail-in ballots or applications if the voter uses a different ID number than what they provided when registering to vote.

The mail ballot rejection rate in Texas' March primary was one in eight, or 12.4%, according to data from the secretary of state's office, compared to Texas' 0.8% mail ballot rejection rate during the 2020 election. Officials blamed the spike in rejected ballots mostly on the new law.

In subsequent, much smaller elections in Texas, the rejection rate fell to less than 4%, which the law's defenders said proved that voters had adjusted to the new requirement. But voter advocates say those elections' turnout was too small to prove the problem was fixed.

WHAT TO EXPECT IN THE 2022 MIDTERMS

With many Americans returning to normal life despite the ongoing coronavirus pandemic, public policy experts such as Fowler believe there will be less demand for mail-in voting in November than there was in the 2020 election. There has also been less criticism of mail-in voting this year, compared to 2020.

But voting rights advocates fear that new restrictions could disproportionately hinder voters of color, such as a 2021 Georgia law shortening the time to apply for and cast mail ballots.

Although turnout in Georgia's June primary was nearly triple that of the 2018 midterm primaries, Brennan Center analysts found that the turnout gap between white and Black voters had also widened to 6 percentage points, the highest disparity in a decade.