"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.

The president says a third term is "not something I'm looking to do," and the U.S. economy is in a "transition period."

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