The 2020 election took days to call. Could it happen again this year?

After the 2020 presidential election took days to call, many states reworked how they process mail ballots with the goal of delivering results faster — and cutting off oxygen for conspiracy theories that flourished as the country waited for results.

Election officials are optimistic that the 2024 vote count will be smoother without the many challenges the pandemic election of 2020 posed to officials. But in the event of a close race, a handful of key battleground states could keep Americans waiting well beyond Election Day yet again to learn who will be president for the following four years.

Clerks in Pennsylvania and Wisconsin — two of the most closely divided states in the 2020 election — still will not be able to process any mail ballots prior to Election Day, despite efforts of state lawmakers to change the rules. That means there could again be a massive pileup of absentee ballots to sort through in those states Nov. 5, along with the in-person vote.

And in North Carolina, a battleground state that has leaned Republican at the presidential level, changes to the state’s voter ID law and early voting process could slow the count.

While longer waits for results are not a sign of problems, experts warn they can be spun that way — as Donald Trump and his allies did in 2020.

“We could have a situation where we just have a couple of bottlenecks,” said Rachel Orey, senior associate director for the Bipartisan Policy Center’s Elections Project. “That creates huge risk for the spread of mis- and disinformation when you have a couple of states in the spotlight, and you have candidates saying — well, we have results from all these other states. Why are you taking so long? There must be something wrong.”

“Ultimately, the responsibility comes down to the candidates,” Orey added. “But that’s easier said than done.”

In Wisconsin, lawmakers again blocked changes to ballot counting processes earlier this month, with the Republican-controlled state Senate holding up a bill that would have allowed election officials to start reviewing mail ballots before Election Day.

Election workers have begged for the change for years, in hopes of speeding up ballot counting — particularly in the densely populated and heavily Democratic Madison and Milwaukee, where Trump allies portrayed slow counting of mail ballots as a sign of fraud in 2020.

“From a perception point of view, it would help a lot,” Dane County Clerk Scott McDonell, the top elections official in Wisconsin’s second most populous county, which includes Madison, said referring to the bill. “There’s no reason to wait” to begin processing the ballots.

“You wouldn’t have absentee results coming in late at night. It takes pressure off 20-hour days, you can get a jump on it. It would be a real improvement to do that,” McDonnell, a Democrat, said.

While Wisconsin Gov. Tony Evers, a Democrat, and the state’s GOP-led Legislature have butted heads repeatedly on elections bills in recent years, the stalemate over the preprocessing bill in question is a product of Republican divisions in the state.

GOP lawmakers in Wisconsin — one of the epicenters of efforts by Trump allies to overturn the results of the 2020 election — remain fractured on how to move forward from the former president’s election denialism.

“I have no idea why senators would not want to solve the problem of these late-night ballot dumps,” Republican Assembly Speaker Robin Vos — whose chamber passed the GOP-sponsored bill allowing Wisconsin elections officials to process, but not count, absentee ballots starting one day before Election Day — told the Milwaukee Journal Sentinel.

The bill stalled in the state Senate when the Republican chair of the election committee refused to move it due to questions raised by an outspoken Trump ally and election denier who is now herself the target of an ethics inquiry related to an effort to oust Vos.

With the bill tabled, even its Republican supporters have said that Milwaukee elections officials will face continued pressure to count ballots rapidly if they want to avoid more baseless conspiracy theories.

Pennsylvania’s election policies and ballot counting drew numerous lawsuits and conspiracy theories from Trump and his allies in 2020. Democratic Gov. Josh Shapiro has pushed for changes that would allow for the influx of mail-in and absentee ballots to be processed ahead of Election Day.

But the state Legislature, where Republicans control the Senate and Democrats have a narrow majority in the House, has failed to advance legislation that would speed ballot counting in November.

One proposal, which would have allowed elections officials to prepare absentee ballots for tabulation seven days ahead of Election Day, stalled in the state House last year over some Republicans’ concerns over ballot secrecy envelopes and voter registration deadlines.

North Carolina’s new voter ID law is expected to significantly slow the counting process, too. The law creates a cure process that gives voters nine days to bring election officials their identification if they don’t have it when they vote. It also allows certain people to vote with a provisional ballot and a voter ID exception form, something that officials say will slow down their counting. Provisional ballots also take a longer amount of time to count.

North Carolina Republicans had been trying to enact a strict voter ID policy in the state for more than a decade, but were repeatedly blocked by courts until last year, when the newly Republican-controlled state Supreme Court reversed an earlier decision to allow the law to take effect.

And the early vote won’t be reported as soon as in previous years, because a new state law requires election officials not to tabulate early voting counts until polls close at 7:30 pm on election night.

“You’re not going to see any results at 7:30 like you did in previous years, you might start seeing them at 8, 8:30,” said Patrick Gannon, a spokesperson for the North Carolina State Board of Elections.

Still, many key presidential election states have taken action since 2020 to update their policies around ballot processing.

Michigan officials will now have a week to preprocess mail ballots, a dramatic increase from the 10 hours that certain counties had to begin reviewing them in 2020. The change comes as the state rolls out huge new voting changes, after a new constitutional amendment required no-excuse mail voting and nine days of early voting to all voters.

In total, 40 states and D.C. now allow some amount of ballot processing prior to Election Day, according to the Bipartisan Policy Center, up from 27 in 2020. And many of those states have extended the time frame for it.

Minnesota officials will have 18 days to preprocess ballots ahead of the election in 2024, up from seven before the pandemic.

“There’s no tally of who’s ahead,” said Minnesota Secretary of State Steve Simon, a Democrat. “It’s figuring out — do they have what they need? Did the absentee voter sign the ballot? Did she have a witness requirement?”

Arizona lawmakers also dodged a possible counting nightmare earlier this month, with bipartisan members approving a tweak to the state’s election code to give officials more time to accommodate automatic recount rules that could have left state officials double-checking ballots well past the deadline for sending their presidential electors to Washington, D.C.

And while Arizona’s ballot-counting procedures have stayed largely the same, its staff has changed: In 12 of the state’s 15 counties, one of the top two election officials has left their post, Arizona Democratic Secretary of State Adrian Fontes told NBC News earlier this month.

Many states have seen high levels of election staff turnover, and new members may struggle with complex policies or new procedures. After conspiracy theories drove an entire county’s elections staff to quit in Virginia, for example, the new staff struggled to report election results in November last year.

“That loss of institutional knowledge could delay or potentially interfere with election operations,” said Orey, from the Bipartisan Policy Center said. “We might see more small mistakes and errors that, while they don’t ultimately impact the integrity of the result, again, become fodder for that misinformation and conspiracy theories.”

This article was originally published on NBCNews.com