Donald Trump is attempting to select his own citizenry and control who can vote by gathering the personal details of all Americans, Arizona’s top election official has warned.

Adrian Fontes, Arizona’s Democratic secretary of state, fears that the Trump administration’s active efforts to forcibly extract voter files from 30 states including Fontes’s own are part of a bigger plan to gather vital information on all US citizens into a centralised database. “Trump is trying to amass a master list that will allow him to declare someone an enemy of the state,” he said.

In his 19th-floor office in Phoenix, Fontes said that in his view Trump wants to create the equivalent of “apartheid in the United States” and likened his actions to those of his counterpart in North Korea. With personal information on all Americans at his disposal, the president could regulate key aspects of the lives of his opponents, including “shutting off their bank accounts, or keeping them from getting healthcare”.

“This is Donald Trump trying to pick his own voters,” he said.

Fontes won a major victory in his running battle with the Trump administration on Tuesday when a federal judge threw out a lawsuit from the US justice department against Arizona over its refusal to hand over its voter roll. The judge, Susan Brnovich, a Trump appointee, ruled that the Department of Justice was not entitled to the document under federal law.

The suit was part of a push by the DoJ to obtain voter roll information from all 50 states, suing 30 including Arizona that have refused to co-operate. At least 13 states have voluntarily complied with the DoJ’s demands, but many others are resisting.

In those cases where courts have ruled on the dispute – California, Oregon, Michigan, Massachusetts and Rhode Island – all judges have found against the administration. Fontes – who was himself sued after he declined to hand over the data, pointing out that it would be illegal under state law to divulge sensitive personal information about almost 5 million Arizonan voters – has joined that list of vindicated parties.

“This is now the sixth federal court to reach the same conclusion. Arizona acted correctly in refusing this request, and today’s ruling vindicates that decision,” he said.

Fontes was elected secretary of state four years ago as part of a sweep by Democrats of top statewide positions. Katie Hobbs was elected governor and Kris Mayes as attorney general.

All three are now in re-election battles facing Republican challengers who have in varying degrees embraced the lie that the 2020 election was stolen from Trump.

Arizona has for years been pivotal to Trump’s efforts to stoke election denial conspiracy theories. Maricopa county, which covers Phoenix, is one of the largest and most electorally consequential swing counties in the country.

In 2020, it was the focus of a fierce battle in which Trump loyalists attempted to declare victory in the face of his defeat to Democratic rival Joe Biden. The Republican-controlled state senate contracted Cyber Ninjas, a private security firm that had no background in election administration, to conduct an audit into Maricopa county’s results.

The audit, which was widely debunked, concluded that Biden had won the election.

Arizona is now back in the crosshairs as the November midterm elections approach. The state has been the subject of at least three federal investigations into its election procedures, with the Trump administration continuing to press unfounded claims that electoral fraud is rife.

The DoJ claims that its data demands aim to root out rampant fraud and voting by noncitizens. Fontes rejects that argument .

“This doesn’t have anything to do with non-citizens, because non-citizens don’t vote. Every study shows that,” he said. “So what you have here is an unprecedented invasion into the privacy of Americans, sold under a false narrative of illegal voting.”

In March the FBI seized a vast stash of digital data that had been compiled by the Cyber Ninjas’ audit of Maricopa county in 2020. Though it is unclear what exactly was in the trove, it is possible that it included details of votes cast and images of actual ballots.

The material was handed over to FBI agents under a federal grand jury subpoena by the Republican president of the state senate, Warren Petersen. Fontes was scathing about Petersen’s decision to cooperate with the subpoena, suggesting it may have broken state data-protection laws.

“He was so quick to turn over the material as a political favor to Donald Trump,” Fontes said. “Clearly he had no intention of protecting Arizona voters or legal processes.”

Petersen’s compliance with the FBI subpoena is likely to be a factor in the mid-term election for Arizona attorney general. He is currently the frontrunner to become the Republican candidate challenging Mayes, the incumbent Democrat.

The third federal investigation into Arizona elections is being conducted by Homeland Security Investigations (HSI), the investigative arm of US Immigration and Customs Enforcement (ICE). It is also taking a renewed look at the 2020 presidential election result in a further bizarre move to relitigate a contest that was settled more than five years ago.

“It’s like herpes,” Fontes said, referring to the perpetual resurfacing of the election denial conspiracy in Arizona. “It just keeps coming back. And I just don’t think the state, or the nation, deserves that.”

Trump’s latest ploy to wrestle control over elections from the states is his executive order last month that tries to limit mail-in voting by creating a national voter file to which the US postal service would have to defer before delivering mail ballots. The order, which is being challenged as unconstitutional, is especially sensitive in Arizona, where 80% of votes are cast by mail in a system devised decades ago, ironically, by the Republican party.

“This is a bald-faced attempt at completely controlling American democracy according to the whims of one political actor, and that’s not just un-American, it’s absolutely anti-American,” Fontes said.

Fontes is gearing up for his own potentially bruising re-election battle in November, in which he is likely to be competing against an election denialist. The two Republicans vying for their party’s candidacy in the secretary of state’s race both have election-denial track records.

Alexander Kolodin, a lawyer, was placed on probation by the state bar association after he filed lawsuits challenging Biden’s 2020 victory that a judge slammed as being full of “gossip and innuendo”.

The other candidate, the former chair of the Arizona Republican party, Gina Swoboda, was the Trump campaign’s director of operations on election day in 2020. She claimed in a lawsuit that was dismissed for lack of evidence that more than 1 million ineligible voters may have been on the rolls.

Fontes said he was “cautiously optimistic” that he and his Democratic peers would sweep the state again in November. But he conceded that “we have to be extra vigilant”.

“We have to spend every single day from now until November focused on communicating as clearly as we can with every Arizona voter,” he said.

Two factors were in play this midterm cycle that would make re-election more difficult, he said: unlike in 2022, there is no US senate race in Arizona this year, so there is less of a draw to attract Democratic voters to the polls.

The other factor he pointed to was that since 2022, the rightwing activist group Turning Point USA has grown in influence. Turning Point, whose leader Charlie Kirk was killed by a gunman in September, is headquartered in Arizona and in Fontes’s view has largely surplanted the old Republican party in the state.

“We’ve got to be cautious because we’re going to be running against the conspiracy theories, lies and misrepresentations,” he said. “The stakes of this election are enormous, and every voter will be impacted by the outcome.”