The Republican National Committee has expanded legal challenges to voting and election procedures in key swing states since March, when presumptive nominee Donald Trump installed new party leaders with a mandate to pursue his unsubstantiated claims of widespread cheating.

In Arizona, Michigan and Nevada, Republicans are seeking to force election officials to remove voters from the rolls, despite federal law limiting such actions in the months preceding an election. In another Nevada lawsuit, the RNC is seeking to block mail ballots from being counted if received after Election Day, using a legal theory that has been repeatedly rejected in other courts and would upend existing practices in many states.

Critics say the challenges are legally frivolous. But the cases are dangerous nonetheless, they argue, because they are meant to further erode public confidence in elections and lay the groundwork to overturn the results if Trump loses.

“This is how you build a story that enables political interference in the post-election process,” said Jess Marsden, a lawyer with the nonprofit Protect Democracy who oversees litigation and advocacy around voting rights.

Trump’s demands for the RNC to take more action on supposed ballot fraud was a key factor in the departure in March of national chairwoman Ronna McDaniel. Trump handpicked her successor, Michael Whatley, and as co-chair selected his daughter-in-law Lara Trump. They took over the central committee with an explicit emphasis on expanding “election integrity” lawsuits and monitoring.

Since then, the party has been filing new lawsuits and publicizing them more emphatically. A recent memo touting the RNC’s accomplishments in the current cycle included cases in Arizona, North Carolina and New York that Republicans lost, as well as a New York case that dealt with local rather than federal elections and a Michigan case from 2022. Lara Trump routinely notes that the RNC has more than 90 active cases, a tally that includes 75 cases filed before 2024 and many in which the RNC played a supporting role with amicus briefs rather than leading the litigation.

“We are pulling out all the stops, and we are so laser-focused on election integrity,” Lara Trump said at the California GOP convention in May. The new party platform approved on Monday adds a plank about election rules that calls for “measures to secure our elections, including voter ID, highly sophisticated paper ballots, proof of citizenship, and same day voting.”

Marsden and others say it is not a coincidence that a vast number of the lawsuits pertain to areas that have long been targets for Trump and other election conspiracists who falsely claim that President Biden’s victory in 2020 was tainted by widespread fraud.

For instance, lawsuits in multiple states arguing that election officials are not properly maintaining voter rolls — thus allowing ineligible people to remain registered — track with one of Trump’s most common unsubstantiated claims: that millions of noncitizen voters are being allowed to cast ballots in U.S. elections.

The lawsuits do not offer evidence of large-scale illegal voting, and the one in Nevada was already thrown out. “The complaint insinuates that voter fraud could happen,” the judge, Cristina D. Silva, said at a hearing last month when she dismissed the case. “That makes this speculative at best.”

Democrats argued the lawsuit was performative because the GOP never asked for fast-track proceedings that could take effect before this November’s election. The judge left open the possibility for the Republicans to come back later with new evidence and arguments.

“We would be fine to continue litigating this case after the election,” the GOP lawyer, Conor Woodfin, said at the hearing.

Similarly, lawsuits in Michigan and Arizona feed off a common Republican complaint about changing election rules to accommodate health concerns during the pandemic, such as allowing drop boxes and drive-through voting. Those cases challenge state election manuals setting out detailed rules on how local officials are supposed to administer elections.

The Arizona suit has already been thrown out. The Michigan case is still making its way through the courts. Democrats and other critics say it is keeping alive the false view that elections can’t be trusted.

“It’s an effort to delegitimize Democrats who are running elections in battleground states and also delegitimize the process writ large in the hopes of using that delegitimization to win legal cases after the election,” said Michigan Secretary of State Jocelyn Benson (D). “We live in a world in which no matter what happens, people are going into this election cycle to try to invalidate as many votes as they can.”

Other suits pertain to the details and rules around absentee voting, which Trump has claimed without evidence to be riddled with fraud. In Michigan, the RNC has claimed a victory in a case over the rules governing the verification of signatures on ballot envelopes.

Although Benson has said the suit will do nothing to change the way clerks validate signatures, others worry there could be a chilling effect among election workers who are reading the headlines and hearing the false claims that thousands of fraudulent ballots could be forged.

Project Democracy has found raising similar doubts about how signatures are validated on absentee ballots in the past has resulted in more being rejected, not always fairly. A comparison by the group between the Georgia general election in 2020 and the two U.S. Senate runoff races the following January showed a spike in rejected signatures. Researchers attributed the increase to an explosion of misinformation, much of it from Trump, about how much cheating occurs among voters using mail-in ballots.

Some of the GOP’s lawsuits are more substantive, creating the possibility that thousands of ballots or voters could be deemed ineligible. The most prominent of these has unfolded in Pennsylvania, where state and federal judges have ruled in favor of the RNC that state law requires mail ballot envelopes to be dated by the voter to be counted.

Although prior court decisions had allowed for undated ballots to be counted so long as they arrived by Election Day, Republicans successfully contested thousands of such ballots in 2022. Voting-rights activists have filed a new lawsuit seeking to overturn that ruling.

“The only date that should matter is the date that is stamped on the envelope when the ballot arrives at the local election office,” said Kathy Bookvar, a former Pennsylvania secretary of state who is now a consultant on election security.

In Nevada, Republicans sued in May to stop mail ballots from being counted if they arrive after Election Day. Their argument, that federal law establishes a national election on a single day, has already been rejected by courts in Illinois and New Jersey. Democrats said adopting that theory would upend widespread early and mail voting practices, “changing the way tens of millions of Americans vote in nearly every state.” An RNC spokeswoman said the party is arguing that voting in person and by mail before Election Day is fine but there has to be a deadline. Nearly two-thirds of states already require ballots to arrive by Election Day.

The flurry of lawsuits this year is in some ways a response to the proliferation of election conspiracies among Trump supporters, who are demanding action from their party. But it also reflects an understanding that a number of the lawsuits filed in 2020 came too late — after the election, when many judges said it was no longer appropriate to consider changing the rules.

By contesting election policies months ahead of November, Republican leaders are trying to establish what those rules will be ahead of time. Democrats fear there is also an ulterior motive.

“Every MAGA Republican lawsuit taking aim at our right to vote looks like another brick in the foundation of their efforts to try to steal this election when they lose in November,” Biden campaign spokesman Charles Lutvak said.

RNC spokeswoman Claire Fortenberry Zunk accused the Democrats of “baseless attacks and name calling because they’re afraid of transparency in our election system.”

Even if some of the cases prevail, less clear is whether such rules will benefit Republican candidates more than Democrats. In Pennsylvania, for instance, officials in some Republican-led counties have said they will not notify voters whose ballots are rejected for a lack of date, while Democratic strongholds such as Philadelphia and Pittsburgh are likely to do the opposite. As a result, more such ballots could be fixed and counted in Democratic-leaning parts of the state than in places controlled by the GOP.

In addition, recent polling shows that the presidential election is likely to be decided by low-information voters — the kind who are less well-versed in the rules of casting ballots and perhaps more likely to commit an error, such as omitting the date on the envelope of an absentee ballot. That could include voters for Biden or for Trump.

Patrick Marley in Madison, Wis., contributed to this report.