Can military forces be used to quash an 'enemy within,' like Trump suggested? Here's what to know

Speaking on Fox News Sunday, former President Donald Trump suggested using the military on U.S. soil to tamp down on chaos on Nov. 5.

When asked if he was worried about foreign-agitated violence on Election Day, he said:

"I think the bigger problem is the enemy within," he said, saying the "radical left-lunatics" could pose a potential problem on Election Day. "It should be very easily handled by, if necessary, by National Guard or if really necessary by the military."

Some Republicans were uncomfortable with this notion, and Vice President Kamala Harris jumped on the comment, showing the video of Trump's interview at a rally in Pennsylvania the next night.

Here is what to know about the president's powers in relation to deploying the National Guard and military.

Interview review: Donald Trump attacks Kamala Harris, praises Fox News

Biden controls military until Inauguration Day

Only the president of the United States has control over the military. That means President Joe Biden will remain the commander in chief until either Trump or Harris is likely inaugurated on Jan. 20, 2025.

The National Guard serves state and federal functions but is largely under control of state governors. The president controls the D.C. National Guard.

Presidents can deploy the military domestically through the Insurrection Act

The Insurrection Act consists of statutes dating as far back as 1792. According to the Brookings Institution, it is the primary law defining the cases in which a president may deploy federal troops in the face of civil unrest. It lays out the following three scenarios for authorizations of force:

• The state requests federal assistance

• A rebellion makes it impossible to enforce federal law

• Some sort of violence or conspiracy is depriving others of their Constitutional rights

The law is meant to be an exception to the core U.S. legal principle that the military should not be involved in civilian affairs.

Trump floated using the military against 2020 summer protests

The Insurrection Act has been invoked many times throughout history, according to the Brennan Center for Justice. Presidents George Washington and John Adams used it to quash early rebellions against federal authority. President Abraham Lincoln used it at the start of the Civil War, and some presidents used it during the civil rights movement to enforce federal desegregation orders.

The last time the Insurrection Act was used was under President George H.W. Bush during the Los Angeles race riots, but it was done so at the request of the California governor, Brennan Center data shows.

Trump wanted to use the Insurrection Act to tamp down protests and riots during the summer of 2020, but was met with pushback from his own administration. Still, he has repeatedly touted such ideas on the campaign trail this season.

Contributing: William Cummings, Ryan W. Miller

This article originally appeared on USA TODAY: Trump wants to stop an 'enemy within': The Insurrection Act, explained