In Pennsylvania, officials are bracing for another presidential election in which the state could once again be the decisive battleground and take days to determine the winner.

Seth Bluestein, a Republican city commissioner in vote-rich Philadelphia, put the odds of knowing the winner on election night at “almost zero.”

In battleground Wisconsin, meanwhile, a final tally isn’t likely until the morning after the election, said Ann Jacobs, a Democrat who chairs the state’s election commission.

While several other states have moved to speed up the vote count in the four years since 2020’s post-election chaos, political gridlock in Pennsylvania and Wisconsin has prevented a change that could have paved the way for earlier projections: the ability to begin opening and processing mail-in ballots before Election Day.

Election observers worry that delays in counting mail ballots could give the public a false sense of who’s winning the election. That could create a potential “red mirage” – showing GOP candidates ahead initially before more Democratic-leaning absentee ballots are processed and added to the tally – and leave an opening for false narratives about election fraud to flourish as the country awaits results. In Georgia, a controversial rule change approved Friday that requires workers to hand-count the number of ballots cast at precincts on Election Day could delay the results of the presidential election in another key swing state.

“It’s obviously a concern,” Pennsylvania Secretary of State Al Schmidt, a Republican, said of the time lag in the Keystone State. “That period of uncertainty is something that is exploited by bad-faith actors to undermine the confidence in the outcome.”

A dayslong wait again

In 2020, it took news organizations four days before projecting that Joe Biden had won the state and, therefore, the presidency. In that time, misinformation festered. Protests broke out at the Philadelphia counting center. Then-President Donald Trump baselessly accused election workers in Pennsylvania of trying to commit fraud. His attorney at the time, Rudy Giuliani, held a now-infamous news conference full of falsehoods at Four Seasons Total Landscaping.

In Wisconsin, another state that Biden flipped on his way to the White House, Trump falsely attributed his loss to “surprise ballot dumps” in heavily Democratic Milwaukee. The jump in Biden votes came when the city reported all of its absentee ballots at the same time – a development that had been widely anticipated because state law prevents the early processing of mail ballots.

In Wisconsin and Pennsylvania, election officials are still barred from beginning to process mail ballots before 7 a.m. on Election Day – even though election workers in both states have clamored for change.

At one point, lawmakers in the Wisconsin State Assembly reached a bipartisan deal to allow clerks to begin processing the ballots the day before the election. But it died in the state Senate after an array of prominent Wisconsin election deniers raised concerns about election security.

“It was conspiracy theories that killed the bill, frankly,” Jacobs told CNN. “I was very disappointed.”

Election observers say a few factors could reduce new conspiracy theories from cropping up this year as ballot-counting continues late into the night. Republican leaders are encouraging the party faithful to vote by mail as part of an effort to bank votes – potentially reducing the perception of an overnight lurch to the left. Trump, however, regularly muddies that message, including by parroting an unfounded claim recently that 20% of mail ballots in Pennsylvania are fraudulent.

Officials in both states are anticipating a lower volume of mail ballots since the pandemic has passed. In Wisconsin, absentee ballots accounted for nearly 60% of the votes in the 2020 general election. In the state midterms two years later, that had fallen to about 29%, according to state data.

In Pennsylvania, meanwhile, the state has made millions in election funding available to counties, many of which have used the money to invest in faster ballot scanners and equipment that helps process mail ballots.

The funding came with a catch: Counties had to agree to count their mail-in ballots continuously without stopping, even if it takes multiple days. So, while the public may go to sleep on election night without knowing the victor in Pennsylvania, election workers will still be counting.

“It’s a real frustration,” Schmidt said of the failure to change state law. “It does not benefit any candidate. It does not benefit any party. It only benefits the public in knowing results earlier and our election officials, who otherwise don’t have to work day and night.”

Election experts in Pennsylvania and elsewhere are preparing the public that it could be multiple days before the presidential race is called.

Processing mail-in ballots takes time. Workers typically first need to verify the voter’s identity, open the ballot-return envelope, remove the ballot and sometimes flatten it, so it can run through a tabulation machine.

Delays are “not fraud, it’s simply logistics,” said Jacobs.

“It’s very, very unlikely that we’ll know who has won the presidency or control of the House on election night,” said David Becker, a former US Justice Department election lawyer who serves as executive director of the nonpartisan Center for Election Innovation & Research.

“This is the way that the process works,” he added. “We shouldn’t expect at 8 o’clock p.m. that we flip a switch and count 160 million, multiple-page ballots with dozens of races on them instantaneously. … It takes time to get it right.”

Outliers

Pennsylvania and Wisconsin are among the outliers in delaying the processing of absentee ballots. Most states – 43 in total – now allow at least some of that work to begin ahead of election day, according to the National Conference of State Legislatures.

Several states have changed their procedures in the wake of the 2020 election, including Michigan, where Democrats have since gained trifecta control of state government. The Wolverine State now allows processing of ballots eight days before the election in communities of at least 5,000 people. Smaller communities can start processing the ballots the day before the election.

Four years ago, it took until Wednesday afternoon to determine that Biden had carried Michigan as workers plowed through mail ballots. The ballot-counting center in heavily Democratic Detroit drew an angry crowd of Trump supporters, who demanded that the count come to an end.

Michigan state Sen. Jeremy Moss, a Democrat who crafted the new law allowing the early processing of ballots, said he draws a “direct line” from the scene that erupted in Detroit to the January 6, 2021, attack on the US Capitol that attempted, unsuccessfully, to stop the transfer of power to Biden.

“I can’t understand why a state wouldn’t want to solve this problem when other states have the exact same frame for processing absentee ballots,” added Moss, who chairs the elections and ethics committee in the Michigan Senate.

New wrinkles in other battlegrounds

In states that allow early processing of mail ballots, other changes to election procedures might still produce some election night delays – particularly if the winning margins are tight, experts warn.

In Georgia, election officials can begin processing absentee ballots ahead of Election Day and a new law since the 2020 presidential election requires counties to report to the secretary of state – an hour after polls close – the results of all early voting and absentee ballots.

But on Friday, a Trump-aligned majority on the Georgia State Election Board approved a new rule that requires election workers to count by hand the number of ballots cast at a polling place to ensure it matches the number of ballots tallied by voting machines.

Voting experts say the new hand-counting requirement will burden election offices with additional work, and they warn that slower results could allow confusion and disinformation to spread.

In North Carolina, where Harris and Trump are waging a heated battle for votes, a new law requires valid mail ballots to be received earlier than in past elections. Even so, election results could be reported later than usual, officials say. Another new provision requires county boards to wait until polls close at 7:30 p.m. on Election Day to begin counting and reporting the results of votes cast during the state’s 17-day early voting period.

Previously, county election boards could tabulate early voting results before poll closings and then report those results immediately at 7:30 p.m. The new law could delay by an hour or more – depending on the county – the posting of unofficial early results, state election officials have said.

“It’s going to be a late night,” which could spur misinformation, Karen Brinson Bell, executive director of the North Carolina State Board of Elections, said at a recent event about election safeguards. “It’s going to raise questions of what is Karen Brinson Bell doing with the ballots? That’s what was on a poster in a protest outside of our election office in 2020, and I’ll get asked that again.”

Additionally, this year marks the first statewide general election in which a photo ID is required to cast a ballot in North Carolina, a change that officials say is likely to drive up the number of provisional ballots that won’t be adjudicated and counted until after Election Day because voters lacked the required identification at the polling place.

In Arizona – a state that Biden flipped by fewer than 11,000 votes out of more than 3 million cast in 2020 – most residents vote via ballots mailed to their homes. Many opt to return those ballots on Election Day at drop boxes or vote centers.

In Maricopa County, which is home to Phoenix and more than half the state’s voters, officials estimate that between 400,000 and 500,000 voters – potentially as much as a quarter of November’s total county electorate – will drop off their ballots on Election Day.

“At 8:01 p.m. in Arizona, it will look very bad for Republicans,” Maricopa County Recorder Stephen Richer said at the election safeguards event.

“In 2020, someone encouraged Republicans to not vote early, instead to vote in person, either on Election Day or drop off your ballot on Election Day,” Richer said in a thinly veiled reference to Trump. But on election night, counties first release their early vote counts and “since 2020, those will be disproportionately blue,” Richer noted.

A new Arizona statute requires officials to count the number of same-day ballot envelopes dropped off at each vote center before officials can shut down the polling place and take the memory cards that have recorded the votes cast that day to a central counting location.

Additionally, election observers say the complexity and length of Arizona’s ballot could further delay the tallying of results. In Maricopa County, the general election ballot covers both sides of two pages – twice the length of the ballot voters encountered four years ago.

On top of federal, state and local candidate elections, this year’s ballot is crowded with more than a dozen initiatives, many placed there by the Republican-controlled state Legislature seeking to bypass vetoes by Gov. Katie Hobbs, a Democrat elected in 2022. (In Arizona, ballot referrals approved by state lawmakers are not subject to the governor’s approval.)

In a state where contests are often decided by razor-thin margins, any glitches or delays can make it harder to call the race. Arizona’s 2022 contest for state attorney general was decided by fewer than 300 votes.

As a practical matter, “it doesn’t take us any longer to count ballots than other jurisdictions,” said Jennifer Liewer, Maricopa’s deputy elections director for communications. But officials in this swing state “fully anticipate our races will be just as close” this year as they have been in other recent elections, she said.

Maricopa is taking steps to help speed up vote tallying on election night, including adding two workers at each of the county’s 246 vote centers who will focus just on counting the number of early ballot envelopes dropped off on Election Day, Liewer said.

Election experts around the country are urging voters to be patient and refrain from making any conclusions if the results aren’t known quickly on election night.

“We’ve got to stop this language that somebody’s ahead or somebody’s behind,” said Moss, the Michigan state legislator. “The winner is the winner when the polls close. We then just find out who the winner is.”

CNN’s Ethan Cohen, Marshall Cohen and Jason Morris contributed to this report.