Election heads toward record turnout — experts warn of early vote 'mirage'

Election night is finally here, and record turnout is expected to hit record turnout after an unprecedented early voting period during which more than 100 million ballots were cast.

So far, the Associated Press has called South Carolina, Kentucky and West Virginia for President Trump, and Virginia and Vermont for Democratic nominee Joe Biden. All of the results so far were expected — although Virginia was a purple state until relatively recently, it's viewed as a solid Democratic state now. Vote counting continues in a number of important states where polls have closed, including Florida, Georgia, Ohio and North Carolina.Trump holds a narrow 22-16 electoral vote lead to start the night.

Biden entered the day leading Trump nationally by more than eight percentage points, according to FiveThirtyEight's polling average. Biden has a similarly large lead in critical states like Michigan and Wisconsin, while holding narrower leads in Florida, Pennsylvania, Arizona, Georgia and North Carolina. While FiveThirtyEight and other election forecasters gave Biden close to a 90% chance of winning, poll guru Nate Silver warned that state polls were significantly tighter than the national polls — and that a 10% chance of winning for Trump "isn't zero."

This election night won't be like any that has come before, largely because of the influx of mail-in and early votes. More than 100 million ballots were cast prior to Election Day, nearly double the 2016 total of early votes, and about 75% of the overall voter turnout in the last presidential election. As many as 150 to 160 million votes are expected to be cast in total, up from about 137 million in 2016.

Nearly 36 million early votes were cast in person while more than 65 million were cast by mail, according to data from the U.S. Elections Project at the University of Florida. The early vote heavily favored Democrats. Republicans edged out Democrats in the in-person early vote 42 to 36 percent in states that reported party registration, but Democratic mail-in ballots outnumbered Republicans 48-27.

Different states have different rules for how they count and report early and Election Day votes. The Cook Political Report's Dave Wasserman cautioned that states like Florida, North Carolina and Texas, which count early votes in advance of Election Day, will first report large portions of the mail-in and early vote, creating a potential "blue mirage" in which Biden may have a big lead that gradually shrinks as Election Day votes are counted. On the other hand, states like Wisconsin, Pennsylvania and Michigan were not allowed to start counting mail-in ballots until this week, meaning that early Election Day results may show a "red mirage" in which Trump holds lead before the bulk of the vote is totaled.

"It will be easier than ever for initial vote tallies to lead untrained eyes astray," Wasserman warned. "So patience is essential for the media and the public, and it's critical to wait for experienced, statistically driven network decision desks to make projections."

Though Trump has baselessly tried to sow doubt in the security of mail-in ballots and bet big on a strong Election Day turnout, some in the president's camp believe that may have been a mistake.

"The team in Pennsylvania was not as prepared as it should be in a state that could decide the presidency," one campaign source told NBC News' Peter Alexander. "When you bank your entire election on Election Day turnout, you have to ask people if they're going to stand in line for two hours."

The latest NBC News/Wall Street Journal poll showed that Biden led 61-35 among self-reported early voters while Trump led 61-32 among the 28% of voters who said they planned to vote in person on Election Day.

Though there has been concern that large numbers of mail-in ballots could be rejected because of the influx of first-time early voters, early data suggests that a lower percentage of such ballots have been flagged than usual. More ballots may still be rejected for various reasons, including late arrival, a growing concern given that U.S. Postal Service processing times slowed down ahead of the election. The USPS told a court on Tuesday that it cannot trace what happened to 300,000 ballots and refused to comply with a court order to sweep 12 postal districts across 15 states to ensure that any found ballots are rushed to be delivered before polls close. A judge later allowed additional time for the agency to comply with the order in certain key swing states.

Trump and the Republicans have also waged legal battles seeking to invalidate late-arriving votes. One case in Pennsylvania surrounding ballots that are postmarked by Election Day but arrive later could still make its way to the U.S. Supreme Court, where new Justice Amy Coney Barrett could cast a deciding vote. But election law experts note that the election would have to come down to that state — and the number of ballots would have to be great enough to swing the entire state's electoral votes — in order to actually impact the presidential race.