President Trump's push to deploy the National Guard across the U.S. as part of his anti-crime crackdown is being challenged in the courts by several Democrat-run cities that he's targeted. Why it matters: Upcoming rulings could redefine the line between presidential power and state authority during public safety disputes.

Illinois and Chicago have sued the Trump administration to block deployment of the National Guard to Chicago, though it was revealed in court that troops are already on the way.