What is the Insurrection Act — and why Trump’s threat to invoke it in Minnesota is rare

President Trump has threatened to invoke the Insurrection Act, a seldom-used 19th-century law that could let him deploy U.S. troops to quell protests in Minneapolis over federal immigration enforcement and ICE-related shootings. The act has only been invoked about 30 times in U.S. history — most recently during the 1992 Los Angeles riots — and legal experts say its use now raises constitutional questions amid disputes with Minnesota officials.