Political parties and groups have filed nearly 100 lawsuits across seven battleground states that could shape how votes are cast and counted ahead of Election Day and the legal battle that’s expected to follow.

The majority of suits were brought by Republicans and allied groups who are focused on rooting out alleged voter fraud, despite the lack of evidence of its occurring in a widespread way, particularly around mail ballot procedures and noncitizen voting.

Many suits have sought to purge voter rolls or bolster signature and voter identification requirements — or invalidate ballots that don’t meet them — while others have looked to revamp different aspects of election administration, including reducing the use of ballot drop boxes and instituting unusual vote-counting protocols, like requiring that ballots be counted by hand.

Lawsuits from Democrats and allied groups have focused mostly on expanding voting access by trying to extend registration deadlines or appealing for broader interpretations of laws about absentee ballots and voter identification.

According to an NBC News review, the groups have filed at least 96 suits since Jan. 1 in the key swing states of Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin, whose Electoral College voters are all but certain to determine outcome of the presidential election — possibly by as few as tens of thousands of votes.

Voting rights experts said the Republican-led suits could help bolster efforts by former President Donald Trump and his allies to challenge the outcome in November if he loses. They said that many of the suits aren't designed to succeed but that they could help sow further distrust in the voting system.

“Americans know how important it is that every vote counts in this election, that our elections are exceptionally close, and that every vote has to be counted. That’s why we have settled rules of the road early on,” said Danielle Lang, the senior director of the voting rights unit at the Campaign Legal Center, a nonpartisan voting watchdog group. “What we are seeing now that is really troubling is a set of lawsuits being filed so very close to an election that are trying to change the rules of the road in a way that would disenfranchise voters.

“A lot of this litigation is, quite frankly, not designed to succeed. It’s just designed to create confusion and chaos,” she added.

Claire Zunk, a spokesperson for the Republican National Committee's election integrity effort, said in a statement that the "operation is committed to defending the law and protecting every legal vote."

"We have engaged, and won, in record numbers of legal battles to secure our election," Zunk said, adding, "We have stopped Democrat schemes to dismantle election safeguards and will continue to fight for a fair and transparent election for all Americans.”

Democratic National Committee spokesperson Alex Floyd said in a statement that Democrats "across the country are ready to stand up against MAGA Republicans’ attacks on our democracy and efforts to sow chaos in our elections, from the polling place to the courthouse."

"We have assembled a robust legal and voter protection team with a proven track record of winning fights to protect voters’ ability to make their voices heard," Floyd added. "We’re ready to stand up for all eligible voters’ access to the ballot box.”

Here is a summary of the suits that have been filed since the start of 2024 across these seven states.

Arizona

In Arizona, where Joe Biden won in 2020 by just over 10,000 votes, any suit that affects even just a few hundred ballots could end up playing a notable role in affecting the outcome of the presidential race.

Republicans have filed suits related to voters who didn't provide adequate proof of citizenship and have sued to challenge various executive orders signed by Democratic Gov. Katie Hobbs that expanded the number of agencies that can help determine rules governing voter registration and ballot drop box locations.

They’ve also sued to challenge the state’s maintenance of its voter rolls, claiming that they are stocked with ineligible voters. Trump-aligned groups have sued several counties, alleging violations of rules governing drop boxes, ballot chain of custody and ballot signature verification practices.

Democrats, meanwhile, have filed suits related to certain county officials’ decisions to refuse to enforce a rule that allows voters who’ve shown up at the wrong precincts to vote in their assigned precincts.

Georgia

In Georgia, where Biden won by fewer than 12,000 votes in 2020, the breadth of litigation topics is especially wide.

A host of Democratic and voting rights groups sued to challenge a new rule from the State Election Board requiring counties to count ballots cast on Election Day by hand (though a judge blocked that rule this month). Groups had also sued to challenge other new rules from the Republican-controlled board, including some related to certifying election results (though another judge’s ruling this month invalidated those rules, as well).

The Georgia Supreme Court on Tuesday declined to take up an emergency appeal from the state Republican Party that would have restored those rules.

Meanwhile, Republicans have filed suits that challenge Fulton County’s poll workers plans, seek to further purge voter rolls and dispute rules in some counties that govern whether and how election officials consider voter eligibility challenges.

Republicans have also filed a suit that tried to revive unfounded concerns over the state's Dominion voting machines. A judge has tossed the suit out; the DeKalb County GOP has appealed.

In addition, a Republican election official in Fulton County who refused to certify the May primary results sued to maintain her ability to not certify those results. The suit was dismissed last month, with the judge ruling that certification isn’t optional.

Voting rights groups have sued to challenge rules that make it easier for private citizens to challenge the eligibility of out-of-state voters.

And Fulton County election officials have sued the State Election Board over its plan to appoint its own election monitors in the county.

Michigan

In Michigan, which Biden carried in 2020 by more than 150,000 votes, Trump allies stoked election chaos in Detroit, and many in that orbit are already planning disarray for this year.

Republicans have been active in litigation, focusing on voter roll maintenance across the state, Detroit’s practices related to election inspectors and absentee ballots.

Michigan is also one of three battleground states where Republicans have filed lawsuits that challenge the legitimacy of some ballots cast by U.S. citizens living abroad, including members of the military. Those suits allege that existing rules that extend overseas voting eligibility to people whose state residency hasn’t been verified mean those particular votes are prone to fraud. A judge rejected the suit Monday.

A federal judge also dismissed an RNC-led lawsuit on Tuesday alleging Michigan's voter rolls were inflated.

In addition, Republicans have broadly targeted a host of rules and practices related to absentee ballots, including challenges to how election clerks verify and process them, and whether absentee ballots with anomalies should be rejected or challenged.

Nevada

A Republican hasn’t won the presidential race in Nevada in 20 years, but Democratic margins of victory have been exceedingly thin in recent cycles (Biden carried the state in 2020 by just 33,00 votes).

In addition to GOP suits seeking to purge the voter rolls, especially of purported noncitizens, Republicans and allied groups have also focused their suits on the enforcement of voter challenges in various counties, as well as state rules allowing the counting of ballots lacking postmarks received up to three days after Election Day (Republicans have asked that officials be blocked from counting such ballots).

Republicans have also sued in Nevada’s two largest counties — Clark and Washoe — to challenge a rule that allows the counting of mail ballots received up to four business days after Election Day.

The Democratic secretary of state this year sued Republican Washoe County elections officials who refused to certify the results of the June primary election. They eventually voted to certify following the suit.

The American Civil Liberties Union, meanwhile, has filed a suit in Nye County challenging a rule by county officials that it says restricts nonpartisan election observers from fulfilling their responsibilities.

North Carolina

While only one Democrat has won the state’s 16 Electoral College votes since 1980, Vice President Kamala Harris is competing and spending aggressively in North Carolina.

Republican suits have focused on scaling back rules that had expanded voter identification procedures (like digital voter identification for students and staff members at the University of North Carolina-Chapel Hill) and the rules governing the envelopes of returned absentee ballots. Republicans are challenging guidance from the State Board of Elections that county elections officials may accept absentee ballots even when they aren’t returned in sealed return envelopes.

GOP groups have also focused on suing to purge the voter rolls, with some challenges specifically alleging large numbers of noncitizen voters on the rolls.

And like in Michigan, Republicans also filed a suit in North Carolina challenging the legitimacy of some ballots cast by overseas voters. A judge rejected the suit Monday.

Pennsylvania

Republicans have filed suits this year in Pennsylvania over a litany of issues, including challenges to wrongly dated mail ballots, drop boxes, voter rolls, absentee ballot return policies, voting machines and provisional ballots.

Pennsylvania's 19 Electoral College voters are key to both campaigns, so the sheer quantity and breadth of the suits could have major ramifications in the battleground state, which Biden won four years ago by about 81,000 votes, voting rights experts said.

Groups both aligned with Democrats and Republicans have directed suits in various counties at how certain absentee ballots should be treated.

One suit has challenged a decision (related to a recent special election) by the Philadelphia Board of Elections not to count mail ballots that were submitted with undated or incorrectly dated outer envelopes. Several other suits have challenged similar rules in other counties.

Another suit, filed by the ACLU of Pennsylvania, challenges a rule in Washington County that it says means voters with defective ballots aren’t being notified that they had a choice that their votes wouldn’t be counted or that they would be given the option of “curing” their ballots.

Relatedly, another Republican suit challenged the ability of all 67 counties in the state to create notice-and-cure procedures for mail ballots. The state Supreme Court dismissed the suit this month.

A group of Republicans also argued in a lawsuit that no county in the state should be allowed to use ballot drop boxes.

Meanwhile, local officials and the ACLU of Pennsylvania reached an agreement to reinstate drop boxes in Luzerne County after a lawsuit. Republicans also sued after Allegheny County officials announced they’d have five drop boxes.

Republicans filed suits in Delaware County challenging the operation of voting machines, alleging that county officials hadn’t properly tested them. One such suit demands that the county be blocked from using the machines and that the vote be hand-counted. In Montgomery County, a Republican suit alleged that officials failed to adequately test voting equipment.

The state Supreme Court ruled last month that counties may reject provisional ballots that have incomplete signatures on their outer envelopes — a potentially meaningful decision that came in response to a Republican suit over such ballots in Luzerne County.

In addition, as in many other states, Republicans have sought stricter maintenance of the voter rolls in Pennsylvania.

Pennsylvania is also among the three states where Republicans have sued to challenge some ballots cast by overseas citizens.

Wisconsin

In Wisconsin, which Biden won four years ago by fewer than 21,000 votes, Republicans have focused on suits that seek to purge the voter rolls — especially in heavily Democratic Milwaukee County.

Notably, several of those suits have been filed just in recent weeks, even though purging voter rolls within 90 days of an election is a violation of the National Voter Registration Act, voting rights advocates have pointed out. Some of the suits have focused on allegations that there are large numbers of noncitizen voters on the rolls.

But the most prominent legal fights have been over absentee ballots and the use of drop boxes. The state Supreme Court ruled in July to reinstate the use of most ballot drop boxes across the crucial battleground state.

Republicans have challenged Wisconsin Elections Commission rules allowing new absentee ballot envelopes, while groups aligned with Democrats have alleged in suits that a lack of options for elderly and disabled voters to return their absentee ballots amounts to a violation of the Americans with Disabilities Act.

Republicans have also alleged in suits that certain counties haven’t hired enough GOP poll workers.

Meanwhile, the Justice Department has sued two counties over their decisions to ban the use of electronic voting machines in federal elections.