Instead of retroactively judging an executive's extraordinary actions in a time of emergency, Congress created statutory bases permitting the President to declare a state of emergency and make use of extraordinary delegated powers. One of 123 emergency statutes under the umbrella of the National Emergencies Act (NEA), IEEPA grants the President extensive power to regulate a variety of economic transactions during a state of emergency. Congress enacted IEEPA in 1977 to rein in the expansive emergency economic powers that it had been delegated to the President under the Trading with the Enemy Act (TWEA). Origins

		The First World War and the Trading with the Enemy Act (TWEA)

The First World War (1914-1918) saw an unprecedented degree of economic mobilization. The statute gave the President exceptional control over private international economic transactions in times of war. The criticisms of TWEA centered on the following:
(a) It required no consultation or reports to Congress with regard to the use of powers or the declaration of a national emergency. The continuing retroactive approval, either explicit or implicit, by Congress of broad executive interpretations of the scope of powers which it confers has converted the section into a general grant of legislative authority to the President…"

		Enactment of the National Emergencies Act and the International Emergency Economic Powers Act

Congress's reforms to emergency powers under TWEA came in two acts. The NEA provided for the termination of all existing emergencies in 1978, except those making use of Section 5(b) of TWEA, and placed new restrictions on the manner of declaring and the duration of new states of emergency, including: 
Requiring the President to immediately transmit to Congress of the declaration of national emergency. Congress also amended the NEA in response to a ruling by the Supreme Court to require a joint rather than a concurrent resolution to terminate a national emergency. In 2001, at the request of George W. Bush Administration, Congress amended IEEPA as part of the USA PATRIOT Act to return to the President the authority to vest frozen assets, but only under certain circumstances:
... the President may ... when the United States is engaged in armed hostilities or has been attacked by a foreign country or foreign nationals, confiscate any property, subject to the jurisdiction of the United States, of any foreign person, foreign organization, or foreign country that [the President] determines has planned, authorized, aided, or engaged in such hostilities or attacks against the United States; and all right, title, and interest in any property so confiscated shall vest, when, as, and upon the terms directed by the President, in such agency or person as the President may designate from time to time, and upon such terms and conditions as the President may prescribe, such interest or property shall be held, used, administered, liquidated, sold, or otherwise dealt with in the interest of and for the benefit of the United States, and such designated agency or person may perform any and all acts incident to the accomplishment or furtherance of these purposes. IEEPA Trends

Like TWEA prior to its amendment in 1977, the President and Congress together have often turned to IEEPA to impose economic sanctions in furtherance of U.S. foreign policy and national security objectives. While initially enacted to rein in presidential emergency authority, presidential emergency use of IEEPA has expanded in scale, scope, and frequency since the statute's enactment. National emergencies invoking IEEPA, however, have increased in frequency and length since its enactment. Originally, IEEPA was used to target foreign governments; however, Presidents have increasingly targeted groups and individuals. As of March 1, 2019, there were 32 ongoing national emergencies; all but three involved IEEPA. On average, emergencies invoking IEEPA last nearly a decade. That initial emergency aside, the length of emergencies invoking IEEPA has increased each decade. Presidents, however, have also used IEEPA to preempt or modify parallel congressional activity. Terminating National Emergencies or IEEPA Authorities

The heart of the curtailment of presidential power by the NEA and IEEPA was the provision that Congress could terminate a state of emergency declared pursuant to the NEA with a concurrent resolution. In several circumstances, Congress has directed the President to impose a variety of sanctions under IEEPA and waived the requirement of an emergency declaration.
The International Emergency Economic Powers Act (IEEPA) provides the President broad authority to regulate a variety of economic transactions following a declaration of national emergency. IEEPA, like the Trading with the Enemy Act (TWEA) from which it branched, sits at the center of the modern U.S. sanctions regime. Changes in the use of IEEPA powers since the act's enactment in 1977 have caused some to question whether the statute's oversight provisions are robust enough given the sweeping economic powers it confers upon the President upon declaration of a state of emergency.
Over the course of the twentieth century, Congress delegated increasing amounts of emergency power to the President by statute. The Trading with the Enemy Act was one such statute. Congress passed TWEA in 1917 to regulate international transactions with enemy powers following the U.S. entry into the First World War. Congress expanded the act during the 1930s to allow the President to declare a national emergency in times of peace and assume sweeping powers over both domestic and international transactions. Between 1945 and the early 1970s, TWEA became a critically important means to impose sanctions as part of U.S. Cold War strategy. Presidents used TWEA to block international financial transactions, seize U.S.-based assets held by foreign nationals, restrict exports, modify regulations to deter the hoarding of gold, limit foreign direct investment in U.S. companies, and impose tariffs on all imports into the United States.
Following committee investigations that discovered that the United States had been in a state of emergency for more than 40 years, Congress passed the National Emergencies Act (NEA) in 1976 and IEEPA in 1977. The pair of statutes placed new limits on presidential emergency powers. Both included reporting requirements to increase transparency and track costs, and the NEA required the President to annually assess and extend, if appropriate, the emergency. However, some experts argue that the renewal process has become pro forma. The NEA also afforded Congress the means to terminate a national emergency by adopting a concurrent resolution in each chamber. A decision by the Supreme Court, in a landmark immigration case, however, found the use of concurrent resolutions to terminate an executive action unconstitutional. Congress amended the statute to require a joint resolution, significantly increasing the difficulty of terminating an emergency.
Like TWEA, IEEPA has become an important means to impose economic-based sanctions since its enactment; like TWEA, Presidents have frequently used IEEPA to restrict a variety of international transactions; and like TWEA, the subjects of the restrictions, the frequency of use, and the duration of emergencies have expanded over time. Initially, Presidents targeted foreign states or their governments. Over the years, however, presidential administrations have increasingly used IEEPA to target individuals, groups, and non-state actors such as terrorists and persons who engage in malicious cyber-enabled activities.
As of March 1, 2019, Presidents had declared 54 national emergencies invoking IEEPA, 29 of which are still ongoing. Typically, national emergencies invoking IEEPA last nearly a decade, although some have lasted significantly longer--the first state of emergency declared under the NEA and IEEPA, which was declared in response to the taking of U.S. embassy staff as hostages by Iran in 1979, may soon enter its fifth decade.
IEEPA grants sweeping powers to the President to control economic transactions. Despite these broad powers, Congress has never attempted to terminate a national emergency invoking IEEPA. Instead, Congress has directed the President on numerous occasions to use IEEPA authorities to impose sanctions. Congress may want to consider whether IEEPA appropriately balances the need for swift action in a time of crisis with Congress' duty to oversee executive action. Congress may also want to consider IEEPA's role in implementing its influence in U.S. foreign policy and national security decision-making.