A cluster of advocacy groups that boast veteran lawyers, voting experts and ex-judges have expanded legal challenges to Donald Trump’s authoritarian executive orders on voting and other presidential actions they see as a “war” on the rule of law in the US.

Heavy legal opposition to Trump’s two executive orders on elections to curb voting rights and supplant the authority of states on election matters has come from the Democracy Defenders Fund, the Campaign Legal Center, the American Civil Liberties Union and kindred groups.

These legal outfits and like-minded allies have won key lawsuits on election issues, plus litigation thwarting Trump’s moves to end birthright citizenship and a $1.8bn slush fund that could have paid money to allies including January 6 rioters he deemed were unjustly charged.

Since Trump returned to power, for instance, Democracy Defenders Fund and the Campaign Legal Center have jointly filed lawsuits against Trump’s 2025 and 2026 executive orders on voting, challenging their constitutionality to set new voting rules that by law are run by the states.

Key legal briefs they filed together include an August one on behalf of several voting rights groups and local officials in two states to block Trump’s March 2026 executive order that would restrict voting by mail and authorize the US Postal Service to implement rules to that end.

Other groups that have accelerated their legal challenges to Trump’s moves to thwart voting rights and expand his executive powers in other ways, include the Brennan Center for Justice, Democracy Forward, members of the Democratic Attorneys General Association and the Washington Litigation Group.

Last month, for instance, 24 Democratic attorney generals and other plaintiffs filed suit to block USPS from moving forward with rules to curb mail voting and in late August won a temporary 14-day restraining order from federal judge Indira Talwani in Massachusetts.

In response, the DoJ’s solicitor general John Sauer on Thursday appealed to the supreme court to lift the injunction, arguing in heated words that the freeze would create “serious, irreparable harm on the federal government, the states themselves, and the voting public”.

On 4 September Talwani made her injunction permanent, writing that implementing Trump’s order so close to the election “threatens disenfranchisement of millions of United States citizens who seek to vote by mail.” She also stressed that “the record includes no evidence relating to fraudulent mail voting to support the rushed implementation.”

Sauer on 6 September responded with another emergency appeal to the high court urging it permit the new USPS rules to go into effect, claiming that it “does not seize control of states’ administration of elections — it simply imposes reasonable preparation requirements for certain election-related mail.”

In a related twist, a detailed whistleblower complaint that Democratic senator Richard Blumenthal of Connecticut released last week alleged that the USPS has been proceeding with a “secretive, rushed” effort to implement Trump’s order that could lead to “catastrophic failure” with this year’s mail-in voting.

About 50 million Americans, the majority of whom are Democrats, vote by mail, according to reports.

With the elections about two months away, the legal groups are stepping up efforts to thwart “self-serving attempts to take over the midterms”, said a former DoJ lawyer, which experts fear may create chaos and disenfranchise millions of voters.

Anna Baldwin, director of voting rights litigation at the Campaign Legal Center, told the Guardian: “The CLC and the DDF have worked closely together on two ongoing lawsuits challenging the president’s unlawful voting executive orders that attempt to dictate election rules. We’ve teamed up in the supreme court on a brief filed by former state and federal judges, including noted conservative judges, that emphasized just how unlawful and dangerous the president’s efforts to dictate election rules are.”

Baldwin, who spent 14 years in the justice department’s civil rights division, said the CLC and the DDF have also “worked together in federal cases filed in Oregon and California to make sure that the DoJ isn’t able to seize voters’ sensitive data by making false claims about non-citizen voting. In cases around the country, the Campaign Legal Center is pushing back on the DoJ’s lawless efforts to vacuum up and aggregate sensitive data to create a national voter file of some sort.”

Further, former ambassador Norm Eisen, the executive chair of the Democracy Defenders Fund, which he co-founded in 2023, told the Guardian that since its inception the DDF has been involved in more than 300 legal cases and matters in three primary areas: elections, the rule of law and anti-corruption.

Eisen said the group, whose board boasts former federal judge and conservative stalwart J Michael Luttig and liberal-leaning ex-federal judge Nancy Gertner, likes to work in conjunction on cases with other ideologically diverse and nonpartisan groups like the CLC and the WLG because “they both have strong bipartisan credibility. It’s a big-tent approach we’ve taken with our election work.”

Eisen said Luttig and Gertner were instrumental in helping recruit dozens of former judges with bipartisan credentials to file amicus briefs on multiple matters including an August one to the supreme court opposing Trump’s 2026 executive order to curb mail voting.

For its part, the WLG this summer hired about half a dozen new lawyers to handle election-related litigation. “As the midterms approach with growing concerns about potential federal interference in elections, we’ve brought on more attorneys to be even more prepared to litigate sensitive matters under acute time pressure,” said James Pearce, a principal with the WLG.

Elsewhere, Sophia Lin Lakin, who leads the ACLU Voting Rights Project, said the group had been “pushing back” on administration efforts to seize personal voting data from states, and said the ACLU has been involved in 26 of 30 legal challenges to the administration on the issue. To date, the administration has lost 23 cases where rulings have been made.

Critics say Trump, the DoJ, the USPS and the Department of Homeland Security seem to be laying the groundwork for further attacks on the nation’s election rules, citing Trump’s false claims about election fraud and his radical plans to change voting rules.

In July in a televised speech, Trump falsely portrayed the nation’s voting system as riddled with fraud and condemned voting by mail and non-citizen voting. “Mail-in ballots are inherently corrupt,” Trump claimed without evidence, even though he voted twice by mail this year.

Trump, who continues to blame voting fraud for his 2020 loss to Joe Biden, also charged that non-citizen voting, which is illegal and historically minuscule, poses a “crisis of election security”. Trump’s fixation on noncitizen voting is belied by a database from the rightwing Heritage Foundation that only cites 100 cases over a quarter-century.

But according to documents reviewed by the New York Times, hundreds of DHS agents have been engaged in a hunt to find noncitizens among registered voters. The chief of the DHS has said ICE agents could be sent to polling places “if there is a threat to that polling place or we’re serving a warrant”.

The DoJ has helped to amplify Trump’s bogus election claims with legal threats and actions.

In July, Harmeet Dhillon, who runs the department’s civil rights division, wrote to officials in 50 states warning that “any election officer, including the chief election officer of the state, who knowingly retains noncitizens on the state’s [voter list] or facilitates noncitizens in receiving and casting ballots could be subject to criminal liability”.

In August, the DoJ announced plans to send a larger-than-usual contingent of 1,000 lawyers to monitor voting nationwide, raising concerns that such large efforts could lead to voter intimidation.

And in a harbinger of coming legal fights, Trump announced on his Truth Social platform last month that the DoJ’s Ed Martin, a key election denialist in charge of pardons, was leaving to handle election-related litigation.

Former DoJ lawyers say administration threats to voting rights make opposition from legal advocates crucial.

Stacey Young, a lawyer who left the department at the start of 2025 after 18 years to found Justice Connection, a group of more than 3,000 ex-DoJ lawyers and other alumni, denounced Trump’s moves “to interfere” with elections.

“The constitution makes clear that the president has no authority over the administration of our elections, but that hasn’t stopped this president, or those he put in power at the justice department, from trying to interfere,” Young said in a statement. “We’re taking these threats seriously and leveraging our collective strengths to protect election integrity, which is key to maintaining a functioning democracy.”

Justice Connection is working with experts in its alumni network to engage with the media, Congress and the public to highlight the justice department’s traditional role in election security and ensuring compliance with federal voting laws.

Other DoJ alumni agree that opposition to Trump’s election agenda is critical.

“These organizations are doing critical work in protecting the ability of people to vote and make their voices heard – a cornerstone of democracy,” said Michael Bromwich, a former DoJ inspector general. “The full-out assault on democracy must be addressed through the courts because Congress has proven itself unwilling and unable to check the undemocratic steps taken by the administration.”

Barbara McQuade, a former US attorney for eastern Michigan who now teaches law at the University of Michigan, said: “Large law firms sent armies of young attorneys to our nation’s airports to represent individuals caught up in Trump’s travel ban. That is not happening any more because of the ‘deals’ they negotiated with the Trump administration in his second term to support his pet causes.

“Thank goodness for groups like the Democracy Defenders Fund, which are attracting top legal talent and challenging some of Trump’s lawless activities. Their work is protecting the rights of all Americans.”

Further, Nick Brown, Washington state’s attorney general, who chairs an election protection group for the Democratic Attorneys General Association, said it has teamed up with some legal advocacy groups such as the Brennan Center, States United and the DDF to hold “strategy sessions” to prepare for potential disruptive moves by the Trump administration in the November elections.

Brown also attacked the administration’s appeal to the supreme court to move forward with Trump’s executive order on voting by mail, despite Judge Talwani’s strong concerns and Democratic attorney generals’ litigation against it.

He said: “As the court said, states’ compliance with this illegal order would be ‘practically impossible’ before the November elections given the unprecedented demands it would put on state and local elections officials. The chaos that would cause is exactly what Trump wants. That’s why we continue to fight for a fair and properly administered election.”

Baldwin too raised strong concerns about the DoJ’s push to get the supreme court to issue a ruling that would expedite Trump’s executive order on voting by mail.

She said: “The DoJ’s slapdash effort at getting the supreme court’s blessing to turn the USPS into a gatekeeper for mail would be a farce, if it didn’t put our fundamental right to vote in the crosshairs. Given the importance of what is at stake, the DoJ’s continued efforts are nothing more than an attempt to foist chaos on the electoral process. But they will fail.”

Other lawyers engaged in key election legal battles and other litigation voice optimism they will prevail.

Tianna Mays, the legal director of the DDF, said: “The Trump administration has declared war on the rule of law, yet our democratic guardrails are still holding. We refuse to stand by idly while this administration flouts the constitution and attempts to eviscerate our institutions.”