What emergency powers has Congress given to the president in times of crisis

When the President declares a national emergency, no powers or authorities made available by statute for use in the event of an emergency shall be exercised unless and until the President specifies the provisions of law under which he proposes that he, or other officers will act.

The President to reallocate funds from other federal governmental operations, and the Defense Production Act, which permits the President to require companies to make supplies necessary for national defense and to prohibit price gouging.

The President might also be able to argue that he can do other things based on the emergency, but we have no emergency powers clause in the US Constitution and courts have generally been reluctant to grant the executive such powers by implication.

Explanation:

"the royal proclamation of 1763"

the social contract theory