Trump suggests invoking the Insurrection Act. But what is it?

President Trump told reporters Monday that he’s willing to invoke the Insurrection Act to send National Guard troops into US cities if necessary.

His statements come amid ongoing tension over his administration’s deployment — or planned deployment — of federal troops to Democrat-led cities in what he says is an effort to clamp down on crime. Critics say the moves are part of an authoritarian posture aimed at crushing dissent.

What is the Insurrection Act? Here’s a quick primer.

What does the law say?

The act, first passed in the young nation in 1792 , allows the president to deploy the military “to suppress rebellion or domestic violence or to enforce the law in certain situations,” according to NYU Law School’s Brennan Center for Justice.

Among the key provisions i