President Trump and his allies have portrayed their efforts to bypass due process as necessary for national security.

As the Trump administration tests the limits of presidential power, here's a look at what the U.S. Constitution says.

"Trump on Jan. 20: 'I will faithfully execute the Office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States.' Trump today: 'I don't know,'" another person wrote.