Let’s review the basic facts of what it means for a president to declare a national emergency.

Q: What is a national emergency?

A: In 1976, Congress passed the National Emergencies Act, which permits thepresident to pronounce a national emergency when he considers it appropriate.

Clinton declared a national emergency during the 1996 Cuba embargo, preventing U.S. ships or aircraft from entering Cuban territory withoutauthorization.

Obama declared a national emergency during the H1N1 Swine Flu epidemic in2009 to activate disaster plans to set up proper patient treatment.

Bush declared a national emergency after the terrorist attacks of Sept. 11, 2001; the order is still in effect.