Voting by mail, which began in the U.S. during the Civil War when soldiers were away from home, has become increasingly popular in recent elections. A surge in mail-in ballots is expected this November as Americans avoid polling places for fear of contracting the coronavirus. But President Donald Trump, who is seeking a second term, and others in the Republican Party are resistant to making vote-by-mail an option for all -- with Trump going so far as to suggest delaying the election until the pandemic eases. The fight is playing out in state capitals and courtrooms around the country, since states have authority for how elections are carried out.

1. Which states allow voting by mail?

In seven states with the most expansive policies -- California, Colorado, Hawaii, Oregon, Utah, Vermont and Washington -- all voters will automatically receive a ballot in the mail, and most of those states will even pay postage for sending it back. In 40 other states, a prospective voter must request a mail-in “absentee” ballot in advance but doesn’t need to provide a reason for wanting it or can simply cite concerns about the coronavirus. In Missouri, Mississippi and Texas, absentee ballots still are reserved only for those who can cite an approved reason, such as that they will be away on Election Day, serving jury duty, or are disabled, elderly or incarcerated. Policies are under review in many states, so this breakdown is subject to revision by Election Day.

2. What’s left to be resolved?

More than 150 lawsuits have been filed in at least 41 states over the mechanics of voting by mail this year. On specific rules and procedures, states vary wildly. Thirty-one require that the signature on the ballot envelope be checked against a signature on file, for instance, while six states and the District of Columbia require a signature but don’t check it. Three states require the ballot be notarized. Alabama requires a copy of the voter’s ID and a signature from two witnesses or a notary public.

3. Where are the battle lines?

Generally speaking, Republicans are seeking tighter regulation of the process, while Democrats are seeking greater leniency. (Conventional wisdom holds that high turnout favors Democrats because it means more nonwhite and low-income voters are participating.) In Minnesota, groups including the NAACP and League of Women of Voters are challenging a requirement that a witness be present when a mail-in ballot is filled out. For those who live alone, that requirement “poses a direct threat to their health because of the COVID-19 threat,” says the NAACP’s complaint. In a lawsuit filed in Pennsylvania, Trump’s campaign and the Republican National Committee seek to ensure that all written ballots are delivered in person or by mail to county boards of elections, not collected at places such as shopping centers, retirement homes, college campuses and municipal government. They also want to disqualify any ballots not received in an unmarked envelope inside the mailing envelope (to guarantee voter anonymity) and to allow poll watchers to be present at “all locations where absentee or mail-in ballots are being returned.”

4. Will all this be resolved before the November election?

Maybe not. If the election is close enough, it might take days if not weeks of counting mail-in ballots to determine the winner. During that time, many of the issues now being litigated might reemerge in new lawsuits and demands for recounts. Election lawyers from both parties can be expected to go through and challenge individual absentee ballots to try to get them thrown out.

5. Is voting by mail safe?

There is little evidence to support claims by Trump and others that vote-by-mail is rife with fraud. In Oregon, which has mailed more than 100 million ballots to voters since 2000, there have been only about a dozen documented cases of fraud. Elections experts say there are numerous safeguards in place to catch stolen ballots, and that it would be extremely difficult to counterfeit mail-in ballots, as Trump has suggested. The most notorious case of vote-by-mail fraud, in a North Carolina congressional race in 2018, was uncovered by elections officials who noticed these kinds of discrepancies. Trump has also cited a local election in Paterson, New Jersey, to support his concerns; local officials say there were unique circumstances unlikely to occur on a national scale.

6. Does vote-by-mail hurt Republicans?

There is also little evidence to support Trump’s contention that vote-by-mail “doesn’t work out well for Republicans.” In fact, studies have found that there is no inherent advantage to either Democrats or Republicans to expanding mail-in voting, and the GOP has long used absentee voting to its advantage in states like Florida and Arizona. At the same time, research has shown that young, Black and Hispanic voters -- who tend to vote more Democratic -- are more likely to have their mail-in ballots rejected. This year might be different, however, as polls have shown Republicans are now more skeptical of vote-by-mail and less likely to say they’ll use it in November, the first time a partisan gap has been seen on the issue.

(A previous version of this story had an outdated breakdown of state policies in first answer.)

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