Voters waited in lines that stretched for blocks to cast their ballots in Georgia's primary elections Tuesday as some complained that the absentee ballots they had requested never showed up. As the sun rose Wednesday, hundreds of thousands of as-yet-uncounted ballots still sit in boxes in county elections offices.

The long lines, onerous waits, missing ballots and slow counts have become a feature of this year's election season. Virtually identical problems have plagued primary elections in Wisconsin, Pennsylvania, Maryland and other states.

Those problems are raising concerns among experts that a massive turnout in November's general election could exacerbate the strain on election administrators who are already stretched to, or beyond, their breaking points.

"This has the potential to make the Florida recount look like child's play," said John Couvillon, a Louisiana pollster who has watched states repeat each other's mistakes with rising alarm.

In the face of a global pandemic that continues to rage across the country, many election administrators have worked to expand access to absentee ballots. Georgia Secretary of State Brad Raffensperger (R) mailed absentee ballot applications to every active voter on the rolls.

And millions of voters across the country have taken advantage of those ballots to avoid having to go to their polling place on Election Day. In Georgia, the use of absentee ballots jumped by more than 2,700 percent over the 2016 primary.

But those applications raise two potential bottlenecks: Voters must return their applications to county election administrators, many of whom are unprepared to process the surge of paperwork. And those same administrators will be tasked with counting the absentee ballots that are cast, potentially delaying results by days, or even weeks.

"It's important to set everybody's expectations about what a mostly vote by mail looks like. People have gotten used to the drama of an election night," said Michael Li, senior counsel at the Brennan Center for Justice's Democracy Program.

In states like Wisconsin and Georgia, voters have reported that they did not receive ballots for which they applied. Wisconsin and Ohio elections officials both discovered batches of ballots in mail processing facilities that were not counted. In states like Pennsylvania and Maryland, hundreds of thousands of ballots were counted long after Election Day.

Maryland's problems were especially egregious, after a Minnesota-based contractor delivered ballots to absentee voters a week late. Baltimore City Council President Brandon Scott (D) had to wait two weeks to learn he had won the Democratic primary for mayor. In Pennsylvania, more than 900,000 votes were counted in the week after Election Day.

"Thousands of applications for absentee ballots weren't handled properly," said Aneesa McMillan, director of strategic communications at the Democratic super PAC Priorities USA, which has been active in litigation aiming to force states to enfranchise more voters. "We have said since March that states will be overwhelmed with absentee ballot applications. They will be overwhelmed with processing those applications."

In the event of a close election, some are concerned that slow counts and reports of overlooked ballots would raise questions about the legitimacy of the final result. President Trump, an absentee voter himself, has raised unfounded concerns that broadening access to mail-in ballots would lead to fraud, despite ample evidence that widespread absentee ballot fraud does not occur.

"Our country could be headed towards an illegitimate election if states cannot hold safe and secure elections where every eligible voter can participate," former Reps. Tim Roemer (D-Ind.) and Zach Wamp (R-Tenn.) said in a statement issued by Issue One, an election reform advocacy group. "If we fail to be ready, if the results are questionable or unverifiable and thousands of eligible voters are denied their basic right to cast a ballot, it will sow widespread anger, distrust, and disillusionment among American voters about our entire democratic system of government."

Those who do not choose to vote by absentee, or who do not get their ballot in the mail because of an error at the elections office, may face the prospect of longer waits in line. Some states have consolidated voting locations, especially in large urban areas, decisions that surveys show disproportionately disadvantage black and brown communities.

"For anybody who thought mail ballots would be the panacea, it's clear that we need to put resources toward in-person voting," Li said. "Even with record numbers of mail ballots, lots of people are going to be voting in person."

A report issued last week by the Brennan Center for Justice found black and Latino voters waited 45 percent and 46 percent longer, respectively, than white voters to cast their ballots in 2018. The report estimated about 3 million voters waited 30 minutes or more to cast a ballot in the 2018 midterms, and blacks and Latinos were disproportionately likely to face long lines.

"We know that this is a coordinated effort to suppress the vote. There's precedent for it," McMillan said. "Poll consolidation is just one of many challenges we're seeing in many urban areas that are further marginalizing the folks whose votes are already suppressed."

Other states face a critical shortage of election workers, many of whom are retirees who might be especially concerned about their exposure to the coronavirus. In Wisconsin, the election worker shortage was so severe that Gov. Tony Evers (D) had to dispatch the National Guard to run Election Day operations.

Polls show an unprecedented level of interest in this year's presidential contest, raising the prospects of the highest level of voter turnout in more than a century. If voters in primaries waited hours, Couvillon said, the wait times in a higher-turnout general election could be multiples more.

"When you're consolidating these polling places to minimize exposure to coronavirus, you're shoehorning people into fewer precincts," he said. "There's still a fixed number of voters who are being extremely inconvenienced because they have less places where they can go vote."