What is a national emergency? How Congress gave the White House broad, far-reaching powers

Roll Call Decoder

Congress is working to come up with an agreement on border security ahead of the government funding expiration date of Feb. 15. But President Donald Trump has said if the deal doesn’t include money for a southern border wall he will declare a national emergency to get it built instead.

How does the president have this power? Roll Call takes a look at how Congress granted the White House broad authority to act in certain emergency situations.