Trump's 'enemy from within' threat spurs critics' alarm about his authoritarian shift

Donald Trump, in a recent interview, suggested his political opponents are more of a threat to the U.S. than top foreign adversaries such as China and Russia when it comes to the 2024 election.

"I think the bigger problem are the people from within," Trump told Fox News anchor Maria Bartiromo. "We have some very bad people. We have some sick people, radical left lunatics."

Then he floated the idea of deploying the military against them on American soil, arguing without proof they would be more likely to sow chaos on Nov. 5 than his supporters -- despite what transpired on Jan. 6, 2021.

"I think it should be very easily handled by, if necessary, by National Guard, or if really necessary, by the military, because they can't let that happen," Trump added.

The dark comments highlight Trump's increasing bend toward authoritarian rhetoric in his third White House campaign, some political scientists told ABC News.

"It's really classic authoritarian discourse," said Steven Levitsky, a Harvard University professor and author of "How Democracies Die," citing examples from 1930s Europe and 1960s Latin America.

"In each of these cases, autocrats used exactly this language: there's an enemy within that's more dangerous than our external enemies and that justifies the use of extra-constitutional measures," he said. "How many times does Trump have to use this rhetoric before we realize that this is not a normal election?"

Trump's "enemy from within" comments come after a history of praising authoritarian leaders in public as well as threats to jail election workers, pledges to take on the civil service and to enact retribution on political enemies if elected -- all of which would significantly stretch the normal limits of executive power.

Vice President Kamala Harris, playing clips of his Fox News comments, painted Trump as "increasingly unstable and unhinged" and "out for unchecked power" at a Pennsylvania rally on Monday.

"He considers anyone who doesn't support him or who will not bend to his will an enemy of our country. It's a serious issue," Harris said. "He is saying that he would use the military to go after them."

Harris added, "This is among the reasons I believe so strongly that a second Trump term would be a huge risk for America and dangerous."

Meanwhile, some Republicans attempted to downplay Trump's comments.

Ohio Sen. JD Vance, Trump's running mate, said he thought they were related to illegal migrants -- despite Trump specifically shifting his conversation with Bartiromo away from undocumented immigrants or foreign actors toward who he called "radical left lunatics."

Virginia Gov. Glenn Youngkin, a Republican, tried to make a similar argument on CNN, in what turned into a tense exchange with host Jake Tapper as Youngkin said he "didn't believe" that Trump was talking about using the military against Democrats.

The Trump campaign, too, suggested the former president's comments were related to immigration.

"The Harris-Biden administration has unconscionably abused our refugee and asylum systems, and turned them into programs to import mass numbers of unvetted migrants from the most dangerous countries on earth, at the expense of Christians and other persecuted religious minorities who those programs were intended to help," spokesperson Steven Cheung said in a statement to ABC News.

Critics expressed concern not only about Trump's comments but how they're being received by the GOP.

"All the time in authoritarian states you see branding of some faction of the political opposition not as loyal opposition but as enemy opposition," said Kim Lane Scheppele, a professor of sociology and international affairs at Princeton University.

Scheppele noted the U.S. has some history with this, such as Republican President Richard Nixon and GOP Wisconsin Sen. Joseph McCarthy's abuses of power to go after perceived political foes.

But there is a key distinction between then and now, she said, in that Nixon and McCarthy were ostracized by their peers.

"This one is really different because Trump's got this mass movement and a set of people who are willing to fight for him," Scheppele said.

Levitsky said so long as Republicans are standing by Trump, "democracy is going to be in trouble."

"I think the most shocking thing is not what Trump said, but the silence that we hear in response to it, particularly among conservative elites who know better, or who should know better," Levitsky said.