Kris Mayes, the attorney general of Arizona, has vowed to fight the incoming Trump administration over key aspects of its immigration policy, including any attempt to set up deportation camps on Arizonan soil or remove thousands of migrant “dreamers” who came to the US as children.

In an interview with the Guardian, Mayes said that any move by Donald Trump in his second presidential term to unpick the rights of dreamers to remain and work in the US would be a “bright red line for me. I will not stand for an attempt to deport them, or undermine them.”

Arizona, a critical border state that will be on the frontline of the struggle over Trump’s plans for mass deportations, has more than 30,000 dreamers, undocumented migrants who entered the US unlawfully as children but who were afforded rights under Deferred Action for Childhood Arrivals (Daca). The program was introduced by Barack Obama in 2012 but has been under relentless attack by Republicans ever since.

“I definitely will be fighting on behalf of dreamers,” Mayes said. “These folks are firefighters, police officers, teachers – they are part of the very fabric of our state and we will protect them.”

Trump tried to scrap Daca protections during his first presidency and was only stopped by a narrow ruling from the US supreme court. He recently softened his position, telling NBC News that he wanted to find a way to allow dreamers to stay in the country, though his apparent U-turn has left many skeptical of his intentions.

The Daca program is already being challenged by Republican states in a lawsuit that is currently before the ultra-conservative fifth circuit court of appeals. The case is almost certain to reach the supreme court, which has a six-to-three supermajority of rightwing justices.

Despite the hurdles facing dreamers, Mayes said she remains optimistic.

“I think the supreme court will ultimately see the merits of protecting them. We want to give the courts the opportunity to make the right decision here, and we’ll be making very strong arguments on that proposition,” she said.

Arizona’s attorney general also had strong words about any attempt by Trump to construct detention camps in her state as part of his plans to mass-deport millions of undocumented immigrants. She said her army of lawyers were also primed to push back on any move to renew family separation, the policy under which thousands of children were taken away from their parents at the Mexican border as part of a “zero tolerance” strategy.

“If Trump tries to engage in family separation, or build mass deportation camps, I will do everything I can legally to fight that. That is not happening in Arizona, not on our soil,” she said.

Mayes added that family separation – which has left up to 1,000 families still rent apart six years later – was “fundamentally anathema to who Arizonans are”.

Mayes and her team have been preparing for months for the anticipated whirlwind of activity as soon as Trump re-enters the White House on 20 January. They have “scoured”, as she put it, Project 2025, the rightwing playbook for a Trump second term compiled by the Heritage Foundation.

She has also been working closely with other Democratic state attorneys general, noting that between them they filed more than 100 lawsuits during Trump’s first presidency, winning 80% of them.

“One of our strengths is that we are doing this very much together, we are united and we are organized,” Mayes said.

The importance of cross-state cooperation is likely to be all the more critical over border issues.

Mayes said that she was working with her Democratic counterparts Rob Bonta of California and Raúl Torrez of New Mexico – with only the Republican attorney general of Texas, Ken Paxton, taking a very different, anti-immigrant approach.

“Three of the four border states have attorneys general in Democratic hands and we are going to fight for due process and for individual rights,” she explained.

A complicating factor is Proposition 314, the ballot measure passed in Arizona in November with a resounding 63% of the vote. It allows state police to arrest any undocumented person who crosses into the US other than at legal ports of entry.

Mayes said that the decision would not deter her from resisting Trump’s unconstitutional moves.

“Proposition 314 tells us that Arizonans are fed up with a dysfunctional border,” she said.

“We are facing a serious fentanyl crisis in our state, and there’s no doubt that Arizonans want our border addressed. But when Arizonans voted for Donald Trump they did not vote to shred the Arizona and US constitution – I strongly believe that.”

What was needed at the border was more federal resources to increase border patrol boots on the ground, boost the interception of fentanyl, and enhance prosecution of drug cartels. What was not needed, Mayes insisted, was Trump’s threatened plan to send in the national guard and even the US military to act as a souped-up deportation force.

“There’s nothing more unAmerican than using the military against Americans,” she said. “It’s clearly unconstitutional, and it’s not something Arizonans want to see.”

Since being elected to the position of Arizona’s top law enforcement officer in 2022, Mayes has established herself as a rising star in the Democratic party capable of negotiating the at times fraught politics of a border state. Her most high-profile act came in April when she indicted 18 people including Trump’s former lawyer Rudy Giuliani and former chief of staff Mark Meadows for participating in the 2020 “fake electors” conspiracy.

A similar prosecution of fake electors in Georgia was recently upended after an appeals court disqualified the Atlanta prosecutor in charge of the case, Fani Willis.

Mayes told the Guardian that despite Trump’s victory in November, she had no intention of dropping the fake electors case. “These indictments were handed down by a state grand jury, and you don’t do justice by popular vote. The case is in the courts now, and that’s where it’s going to stay until it’s over.”

Such a prominent prosecution could place her in the crosshairs of Kash Patel, Trump’s pick for director of the FBI. Should Patel be confirmed for the job by the US Senate, he has made it clear he will pursue revenge investigations against those deemed to be Trump’s enemies.

Mayes didn’t want to discuss Patel’s nomination. But she did say: “I’m not afraid of anyone. I’m going to do my job, uphold the law and protect Arizonans. I’m going to do it no matter who is at the helm of the FBI.”