By Andy Sullivan

WASHINGTON (Reuters) – With the number of Americans voting by mail on Nov. 3 expected to nearly double due to COVID-19, election experts see little reason to expect an increase in ballot fraud, despite President Donald Trump’s repeated claims.

Voting by mail is not new in the United States — nearly 1 in 4 voters cast 2016 presidential ballots that way. Routine methods and the decentralized nature of U.S. elections make it very hard to interfere with mailed ballots, experts say.

While mail balloting has its drawbacks, it can help minimize the long lines, faulty voting machines and COVID-19-induced staffing shortages that have plagued some elections this year.

HOW SECURE IS IT?

Election experts say it would be nearly impossible for foreign actors to disrupt an election by mailing out fake ballots, a scenario floated by Attorney General William Barr.

For one thing, voters won’t just be selecting a president: They might be choosing candidates for city council, school board and weighing in on ballot initiatives. That can require hundreds of different ballot designs in a single county and the United States has more than 3,000 counties.

Ballots aren’t counted if they aren’t printed on the proper type of paper and don’t include specific technical markings.

States also require voters to sign the outside of their envelope, which they match to a signature on file.

Some 29 states and the District of Columbia allow voters to track their ballots to ensure they are received, according to the National Conference of State Legislatures. Fourteen states and D.C. also allow voters to return their ballots by hand if they don’t trust the mail.

Those envelopes are typically opened by a different group of workers than those who scan the ballots. Outside observers are allowed to monitor the process to ensure voter privacy.

IS FRAUD A PROBLEM?

As with other forms of voting, documented cases of mail-ballot fraud are extremely rare.

The conservative Heritage Foundation, which has warned of the risks of mail voting, found 14 cases of attempted mail fraud out of roughly 15.5 million ballots cast in Oregon since that state started conducting elections by mail in 1998.

The most prominent cases of mail fraud have involved campaigns, not voters. North Carolina invalidated the results of a 2018 congressional election after state officials found that a Republican campaign operative had orchestrated a ballot fraud scheme.

Experts say those scenarios can be minimized by nixing requirements — currently in place in 11 states — which instruct voters to get at least one witness to sign their return envelopes.

“All of these policies remove the need to hand over your ballot to someone you don’t know,” said Tammy Patrick, a former election official in Maricopa County, Arizona.

DOES IT HELP TURNOUT?

Turnout rates tend to be higher in states that conduct elections by mail. A Stanford University study found that participation increased by roughly 2 percentage points in three states that rolled out universal voting by mail from 1996 to 2018. It had no effect on partisan outcome and did not appear to give an advantage to any particular racial, economic or age group.

In Colorado, 77% of voting age citizens cast ballots in the 2016 presidential election, the highest figure in the country, according to the U.S. Election Assistance Commission. In Oregon, that figure was 72% and in Washington it was 68%, well above the national rate of 63%.

ARE THERE BARRIERS?

Like any other voting method, mail balloting has its drawbacks.

States rejected 1% of returned ballots in 2016 for arriving too late, missing signatures or other problems, according to EAC figures — though that figure was as high as 5% in some states. It can be more difficult to fix errors on mail ballots than on those cast in person, experts say.

Mail ballots can pose additional barriers to those who don’t speak English or have disabilities, and delivery can be problematic on Native American reservations, where residents sometimes don’t have street addresses.

In California, which started transitioning to mail ballots in 2018, Black and Hispanic voters were twice as likely to cast their ballots in person, according to David Becker, head of the Center for Election Innovation and Research.

(Reporting by Andy Sullivan; Editing by Scott Malone and Aurora Ellis)