How Trump's Insurrection Act threat raises stakes in Minnesota

First President Trump flooded the Twin Cities with federal agents. Now he's threatening to deploy troops to bolster the armed immigration crackdown.

The big picture: Minnesota is already a tinderbox. An an ICE agent shot and killed a driver in Minneapolis last week, protests have erupted, and Gov. Tim Walz is battling the White House. Deploying troops could add gasoline to the fire.

• Trump is eyeing the Insurrection Act — a rarely invoked power that lets the president put soldiers on American streets. No president has used it since 1992.

Driving the news: Trump vowed Thursday to act unless state officials "stop the professional agitators and insurrectionists from attacking the patriots of I.C.E."

• Walz denounced the crackdown as "a campaign of organized brutality" and an "occupation" of Minnesota.

State of play: Protests have erupted across the country after the fatal shooting of Renee Good, turning Minnesota into ground zero for clashes between demonstrators and federal agents.

• Trump's threat came hours after the another Twin Cities ICE shooting. An agent shot a Venezuelan man in the leg during what the Department of Homeland Security described as an ambush.

Here's what to know about the Insurrection Act:

What is the Insurrection Act?

The provisions of U.S. code that make up the Insurrection Act give the president the authority to deploy troops on American soil.

• One section requires state consent. The others do not.
• Those other sections allow him to deploy troops to enforce laws, suppress rebellion or respond to "domestic violence" that deprives people of their constitutional rights.

Between the lines: The Brennan Center calls it the "primary exception" to the Posse Comitatus Act, which bars federal troops from civilian law enforcement.

• The Posse Comitatus Act emerged in legal debates over the president's recent deployments. A federal judge ruled Trump's use of the National Guard in the L.A. area ran afoul of it.

Threat level: Constitutional scholars have cautioned that the Insurrection Act is ripe for misuse and have called for updates to more narrowly tailor the broad authority.

• "The Insurrection Act should only be invoked in the most extreme circumstances," said David Janovsky of watchdog group Project on Government Oversight in a statement. "That is not what's happening here."

How has the Insurrection Act been used in the past?

The Insurrection Act has been used more than two dozen times before. Throughout its centuries-long history, the act was mainly used to quell riots and labor strikes nationwide.

• In the 1870s, Ulysses S. Grant invoked it to combat white supremacist violence and protect Black voters.
• In 1894, Grover Cleveland used it to break the Pullman railroad strikes.
• Dwight Eisenhower deployed troops in 1957 to protect Black students in Arkansas after the Brown v. Board of Education decision.

The last president to use it was George H. W. Bush, who invoked the act twice during his presidency — once in 1989 over looting in the U.S. Virgin Islands after Hurricane Hugo and again in 1992 over the Rodney King riots.

Go deeper: Unrestrained Trump flirts with Insurrection Act as Marines deploy to L.A.