For decades, the US Department of Justice has used a tool to sniff out former Nazis who lied their way into becoming American citizens: a law that allowed the department to denaturalize, or strip, citizenship from criminals who falsified their records or hid their illicit pasts.

That power, under the new Trump administration, may be broadening.

According to a memo issued by the Justice Department last month, attorneys should aim their denaturalization work to target a much broader swath of individuals ? anyone who may ?pose a potential danger to national security.?

The directive appears to be a push towards a larger denaturalization effort that fits with the Trump administration?s hardline immigration policies. These could leave some of the millions of naturalized American citizens at risk of losing their status and being deported.

People who have committed violent crimes, are members or associates of gangs and drug cartels or have committed fraud should also be prioritized, the memo, issued by the head of the DOJ?s Civil Division, said.

But for many officials and experts, the real concern, they say, is that it is designed to strike fear in the hearts of legal immigrants across the country ? particularly those who are at odds with Trump himself.

?The politicization of citizenship rights is something that really worries me, I think it?s just flatly inconsistent with our democratic system,? Cassandra Burke Robertson, a law professor at Case Western Reserve University, told CNN.

Reshaping immigration

The statute in question is part of a McCarthy-era law first established to root out Communists during the red scare.

But its most common use over the years has been against war criminals.

In 1979, the Justice Department established a unit that used the statute to deport hundreds of people who assisted the Nazis. Eli Rosenbaum, the man who led it for years, helped the department strip citizenship from or deport 100 people, and earned a reputation as the DOJ?s most prolific Nazi hunter.

Rosenbaum briefly returned in 2022 to lead an effort to identify and prosecute anyone who committed war crimes in Ukraine.

But the department has broadened those efforts beyond Nazis several times, including an Obama-era initiative called Operation Janus targeting those who stole identities to earn citizenship.

In 2020, Trump attempted to expand denaturalization efforts by creating a dedicated office at the Justice Department, but it was quietly disbanded by the Biden administration the following year.

One former DOJ official called the office a ?branding opportunity,? noting that it was not particularly effective and did not fit with Trump?s successor?s priorities.

Since returning to the White House, Trump has worked to redesign how the federal government enforces immigration in the country, pushing agencies like the FBI and US Marshals to join deportation efforts and targeting foreign student visas for people abroad hoping to attend a private university in the states.

Instead of reinstating the stand-alone office from his first administration, the entire Civil Division is now being told to prioritize denaturalization ?in all cases permitted by law,? according to the memo, which also suggests that US attorneys? offices across the country should flag cases where they may be able to initiate denaturalization proceedings.

Trump filed 102 denaturalization cases during his first administration, contrasted with the 24 cases filed under Biden, DOJ Spokesperson Chad Gilmartin said on social media Wednesday. So far, the second Trump administration has filed 5 cases in its first five months.

Political consequences?

The DOJ told CNN in a statement: ?Denaturalization proceedings will only be pursued as permitted by law and supported by evidence against individuals who illegally procured or misrepresented facts in the naturalization process.?

But current and former DOJ officials who spoke to CNN said that the beyond instructing lawyers to file as many denaturalization cases as possible, the memo is so broad that it could allow the Justice Department to invoke vague or unsubstantiated claims to expel people from the country.

Robertson, of Case Western, warned that the memo could give way to the Trump administration retroactively searching for missteps in the naturalization process of perceived political opponents, like student activists.

Irina Manta, a law professor at Hofstra University, said that the administration?s move could have a ?chilling effect? on free speech, both political and otherwise.

?I regularly observe the fear firsthand,? she said.

Trump has publicly flirted with the notion of deporting American citizens he doesn?t want in the country.

Though the seriousness of these statements is highly unclear, he has called for everything from deporting ?bad people ? many of them [who] were born in our country? to saying his administration should ?take a look? at removing Elon Musk after his erstwhile ally criticized the president?s spending bill.

At least one ally has taken a more formal step.

Last week, Andy Ogles, a Republican congressman, asked Attorney General Pam Bondi to investigate whether New York City mayoral candidate Zohran Mamdani?who was born in Uganda and naturalized in 2018? should be subject to denaturalization proceedings because he ?publicly glorifies? people connected to Hamas in a rap song.

Bondi has not publicly responded to the letter. (CNN)

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