In all five states, officials have contended with an avalanche of mail ballots as voters seek to avoid exposure to the novel coronavirus. It was a fresh illustration of how the pandemic is transforming the way elections are conducted in the United States.

It is also a stark preview of what’s coming on Nov. 3 — or, more accurately, what may not be coming: an election night result in the race for the White House.

If voters remain reluctant to cast ballots in person, November is likely to bring an even more massive wave of voting by mail than what has swept across the country during primary season. That, in turn, means that a close race between President Trump and former vice president Joe Biden, the presumptive Democratic nominee, in a pivotal state could take days, even weeks, to resolve, election officials across the country are warning.

Barring a landslide for either candidate, that scenario could invite an unprecedented test of the country’s faith in its elections: an extended period without a declared winner. Amid that uncertainty, few expect Trump, who has said repeatedly that he thinks mail voting could cost him the election, to soothe voter anxieties.