What does a national emergency mean in the united states

National emergency can be defined as a state of national crises that threatens not just a part of the nation but the whole, and requires an unprecedented response and requires instantaneous reaction.

Explanation:

National emergency can be defined as a state of national crises that threatens not just a part of the nation but the whole, and requires an unprecedented response and requires instantaneous reaction.

It can also be said to be an extraordinary situation that threatens the health, safety and environment of the citizens that requires intervention by the government.

In the United States, the government at such a time will be required to act in a way that it would not be normally permitted to.

Example in the recent case of COVID-19 outbreak. Since it threatens the lives of people everywhere in the country not just in one state, it is a national emergency and has required the intervention of the government by an unprecedented declaration of a stimulus package of $850 billion dollars, and the request of restriction of the movement of people and closure of airports which will not normally happen.