Six key swing states — Arizona, Florida, Michigan, North Carolina, Pennsylvania, and Wisconsin — permit voters to cast mail-in ballots for any reason. Nonetheless, Ronald Brownstein notes (“The Most Important 2020 States Already Have Vote by Mail”), there is still much room for partisan disagreement in the coming months, as Democrats push to make voting simpler and easier, while Republicans oppose such efforts (even though in states that permit voting by mail — such as Arizona — Republicans may cast most of the mail-in ballots). Among the stickiest issues:

Partisan conflicts could erupt over how exactly citizens can request absentee ballots (many don’t allow them to do so online); whether the state will pay the postage to return the ballot (Michigan, Florida, and Pennsylvania are among those that don’t); and whether, amid the outbreak, states should still require voters to obtain witness signatures before submitting their ballot (as North Carolina and Wisconsin, among others, do). “Probably … tens of thousands of people will have difficulty getting those witnesses,” Morris said.

The most contentious subject will be the standards used to judge which ballots are rejected, particularly on the grounds that a voter’s signature doesn’t match records on file.

Daniel A. Smith, a University of Florida political scientist, has found that mail ballots in that state from young people and minorities are rejected at higher rates than those from older people and white voters—a dynamic that has obvious benefits for Republicans. In some states, Weiser noted, the election officials determining whether to accept a ballot can see on their screen the age and partisan affiliation of the voter they are assessing. Stewart told me he anticipates “a lot of litigation about the rejection of absentee ballots.” [My emphasis.]

This could be decisive in one or more battleground states. Imagine, hypothetically, a case going before the U.S. Supreme Court. A voter’s mail-in ballot has been disqualified because her signature doesn’t match — according to the county election officer, who happens to be a Republican — the signature on the envelope containing the ballot. The voter, who happens to be African American, has filed an affidavit attesting that the signature is hers, and the ballot that she cast is inside the sealed envelope. Suppose hundreds or thousands of additional voters from Democratic areas have had their ballots disqualified based on their signatures.

Recall that the Republican majority in the Supreme Court’s Bush v. Gore decision stopped local officials from counting ballots in Florida in 2000, giving the election to the Republican candidate for president. Suppose in our hypothetical that a ruling in favor of the voters who wish their votes to be counted, would likely tip the state to Joe Biden, while a ruling in favor of the local official would likely tip the state to Donald Trump: how likely is it that the Republican majority on the current Court would decide in favor of voters?

This past week in Wisconsin, mostly Democratic voters did not receive the mail-in ballots soon enough to vote by mail. The Court’s majority found that the right to vote was of lesser importance than a “narrow, technical question” of the law. Suppose such a scenario plays out in November. Suppose, even, that Republican election officials are suspected of either slow-walking the process or simply find themselves unprepared to meet the demand for mail-in ballots? How likely is it that the Republican majority on the Supreme Court would side with voters and against local officials?

Signature requirements – and the possibility of failures by state and local government, including deliberate failures – are huge red flags for anyone who supposes that Republicans are ready and willing to cheat, if necessary, to win an election.

(Image from New York Times‘ Retro Report on Florida in 2000 on YouTube.)