The promise of mass deportations was central to Trump’s campaign and helped propel him to victory on Nov. 5. In one of his first interviews post-election, Trump told NBC News “there is no choice" but to forcibly expel millions of people living in the U.S. without documentation.

The lawsuit alleges that U.S. Immigration and Customs Enforcement has failed to respond to requests for basic information about matters, including flights.

Can Trump really deport 11 million people? Will he deploy the military? Who is “border czar” Tom Homan? Here’s what we’ve learned so far.