Why we might not get a presidential winner on election night

On Nov. 5, voters across the United States will head to the polls to cast their ballots in the 2024 presidential race between Vice President Kamala Harris and former President Donald Trump. But as was the case in 2020, they might not know the results on election night.

That's because it takes time to count the votes — record numbers of which have been cast before Election Day. And in a race that's expected to be extraordinarily close, more votes will need to be counted before a winner can be called.

Individual states determine their own laws and timelines for processing ballots, including those submitted during the early voting and mail-in period. In 2020, during the COVID-19 pandemic, 46% of voters opted for mail-in ballots, according to the Pew Research Center. And the surge in mail-in balloting combined with ballot-counting rules that differ by state led to days of waiting for a result. Joe Biden wasn't officially declared the winner until Saturday, Nov. 7, four days after Election Day. During the gap in reporting results, Trump and his supporters spread election fraud conspiracy theories — baseless claims that they continue to make.

For this election, some swing states, including Nevada and Michigan, have new laws and policies designed to expedite ballot counts. But others, including the battlegrounds of Pennsylvania and Wisconsin, still don't allow the counting of absentee and mail-in ballots until Election Day — which could prolong the process of declaring a winner, especially in such a tightly contested presidential election.

“We are counting ballots faster than ever before,” David Becker, executive director of the nonpartisan Center for Election Innovation & Research, said on a call with reporters. “But when the margins get tighter, it takes more ballots to count until we can call a race.”

And even in states that have tried to speed things up, there are several factors that could have Americans again waiting to find out who won.

“I think it’s likely towards the end of the week — Thursday, maybe Friday — we should have an idea of who won the presidency,” Becker said in response to a question from Yahoo News.

Here’s a quick guide to when battleground states were called in 2020, as well as changes to the vote-counting process for 2024.

Battleground states

Pennsylvania

2020 results (margin): Biden +1.2% (80,555 votes)

When it was called by the AP: Saturday, Nov. 7, at 11:25 a.m. ET

Pennsylvania doesn’t allow mail-in ballots to be counted until 7 a.m. on Election Day, a process that took several days in 2020. (That year, the Associated Press did not call Pennsylvania for Biden until Saturday, four days after Election Day.) And election officials say it will likely take days again this year, especially since the state legislature refused changes that would have expedited the vote count.

Wisconsin

2020 results (margin): Biden +0.6% (20,682 votes)

When it was called by the AP: Wednesday, Nov. 4, at 2:16 p.m. ET

Like Pennsylvania, Wisconsin doesn’t begin processing its mail-in ballots until Election Day. And the state legislature refused to change the law to allow election workers to do so in advance, which may again lead to a lag in a race call.

Michigan

2020 results (margin): Biden +2.8% (154,188 votes)

When it was called by the AP: Wednesday, Nov. 4, at 5:56 p.m. ET

Four years ago, it took until Wednesday afternoon to determine that Biden had carried the middle state in the so-called blue wall, due in part to a law that did not allow the counting of mail-in ballots to begin until Election Day. Michigan now allows those ballots to be processed eight days before the election in communities of 5,000 or more people — including Detroit.

Georgia

2020 results (margin): Biden +0.2% (11,779 votes)

When it was called by the AP: Thursday, Nov. 19, at 9:25 p.m. ET

In 2020, it took weeks to get an official race call from Georgia, during which time Trump and his allies pressured state election officials in an effort to overturn the results. But the state made changes to the law in 2021, allowing mail-in ballots to be processed (but not tabulated) before Election Day while requiring that all counties tabulate their results by 5 p.m. the day after the election. And a Georgia state court recently blocked a new rule that would have required election workers to count ballots by hand.

Arizona

2020 results (margin): Biden +0.3% (10,457 votes)

When it was called by the AP: Wednesday, Nov. 4, at 2:51 p.m. ET

In Arizona, most residents vote via ballots mailed to their homes, and many return them at drop boxes on Election Day. The process of verifying signatures on those ballots takes time and could delay the results, especially in such a close race. In 2020, Arizona was decided by a vote margin even slimmer than Georgia’s. And in 2022, the vote count for the gubernatorial election went on for days after the state received a last-minute flurry of mail-in ballots.

Meanwhile, a federal judge recently rejected a request for Arizona to verify the citizenship of some 42,000 voters registered only to vote in federal elections, which could have added more time to the count.

Nevada

2020 results (margin): Biden +2.4% (33,596 votes)

When it was called by the AP: Saturday, Nov. 7, at 12:13 p.m. ET

Nevada changed its election laws after 2020 to try to release its results sooner, allowing ballots submitted during the early voting period to be counted when the polls open — rather than when they close — on Election Day.

In a statement, Nevada Secretary of State Francisco Aguilar said the changes were made to "increase transparency, help us combat misinformation and alleviate pressure on election officials."

Still, ballots postmarked before Election Day and arriving up to four days afterward will also be counted, which could make the changes moot.

North Carolina

2020 results (margin): Trump +1.3% (74,483 votes)

When it was called by the AP: Friday, Nov. 13, at 4:35 p.m. ET

In North Carolina, a new law requires county boards to wait until polls close on Election Day to begin counting and reporting the results of early voting, potentially delaying the count by hours or more.

“It’s going to be a late night,” Karen Brinson Bell, executive director of the state’s Board of Elections, said at a press conference earlier this month.

And even in states that allow early votes to be counted early, there’s a good chance they won’t be totally done by the time in-person voting starts. New laws in some states require extra verification and opportunities for voters to correct or “cure” mistakes on ballots, which can also add a lot of time to the processing.

How Helene could affect voting in swing states

There is, however, also some good news regarding the impact of Hurricane Helene on voting in North Carolina and Georgia.

In North Carolina, which was devastated by Helene, the state's election board unanimously approved a slate of emergency measures that will allow officials in the 13 most affected counties to modify times and locations for early voting sites, loosen restrictions on absentee ballots and give them more freedom to recruit poll workers. And in those counties, 75 of 80 early voting sites were able to open as scheduled.

In Georgia, which was also hit hard by Helene, Secretary of State Brad Raffensperger reported shortly after the storm that election offices across the state had been "spared from substantial, long term damage."

And on Oct. 15, Georgia set a new record for the most votes on the first day of early voting, with more than 305,000 votes cast, shattering the previous record of 136,000 in 2020.

Read more from Yahoo News:Key swing states rush to ensure Hurricane Helene won't upend the 2024 election

Delays don’t mean fraud

Even if it does take days to declare a winner, as it did in 2020, it doesn’t mean anything nefarious is going on. It just means the election was as close as it was expected to be.

“It’s normal that it takes a period of days to get results,” Becker said. “That’s the way it should be."

“We want them done accurately,” he added. “And anyone who is casting doubt on that process while that process is ongoing probably thinks that they lost.”