They are not limited to military or war situations. Some of these authorities, deriving from the Constitution or statutory law, are continuously available to the President with little or no qualification. It may be argued, however, that the granting of emergency powers by Congress is implicit in its Article I, Section 8, authority to "provide for the common Defense and general Welfare;" the commerce clause; its war, armed forces, and militia powers; and the "necessary and proper" clause empowering it to make such laws as are required to fulfill the executions of "the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof." The Emergency Concept

Relying upon constitutional authority or congressional delegations made at various times over the past 230 years, the President of the United States may exercise certain powers in the event that the continued existence of the nation is threatened by crisis, exigency, or emergency circumstances. During this span of years, however, the exercise of emergency powers by President Abraham Lincoln brought the first great dispute over the authority and discretion of the Chief Executive to engage in emergency actions. During the Wilson and Roosevelt presidencies, a major procedural development occurred in the exercise of emergency powers—use of a proclamation to declare a national emergency and thereby activate all standby statutory provisions delegating authority to the President during a national emergency. A more likely course of action would seemingly have been for the President to declare a national emergency pursuant to the National Emergencies Act and to specify that he was, accordingly, activating the suspension authority.
The President of the United States has available certain powers that may be exercised in the event that the nation is threatened by crisis, exigency, or emergency circumstances (other than natural disasters, war, or near-war situations). Such powers may be stated explicitly or implied by the Constitution, assumed by the Chief Executive to be permissible constitutionally, or inferred from or specified by statute. Through legislation, Congress has made a great many delegations of authority in this regard over the past 230 years.
There are, however, limits and restraints upon the President in his exercise of emergency powers. With the exception of the habeas corpus clause, the Constitution makes no allowance for the suspension of any of its provisions during a national emergency. Disputes over the constitutionality or legality of the exercise of emergency powers are judicially reviewable. Both the judiciary and Congress, as co-equal branches, can restrain the executive regarding emergency powers. So can public opinion. Since 1976, the President has been subject to certain procedural formalities in utilizing some statutorily delegated emergency authority.
The National Emergencies Act (50 U.S.C. §§1601-1651) eliminated or modified some statutory grants of emergency authority, required the President to formally declare the existence of a national emergency and to specify what statutory authority activated by the declaration would be used, and provided Congress a means to countermand the President's declaration and the activated authority being sought. The development of this regulatory statute and subsequent declarations of national emergency are reviewed in this report.