The International Emergency Economic
Powers Act (IEEPA), the National Emergencies
Act (NEA), and Tariffs: Historical Background
and Key Issues
Updated April 7, 2025
On April 2, 2025, President Donald J. Trump declared a national emergency and announced that he would
be imposing a 10% tariff on most imports to the United States and additional duties on certain trading
partners. President Trump cited the International Emergency Economic Powers Act of 1977 (IEEPA) (50
U.S.C. §§1701 et seq.) as his underlying authority. IEEPA may be used “to deal with any unusual and
extraordinary threat, which has its source in whole or substantial part outside the United States, to the
national security, foreign policy, or economy of the United States,” if the President declares a national
emergency under the National Emergencies Act (NEA) (50 U.S.C. §§1601 et seq.) with respect to that
threat. IEEPA authorizes the President to “regulate” a variety of international economic transactions,
including imports. Whether “regulate” includes the power to impose a tariff, and the scale and scope of
what tariffs might be authorized under the statute, are open questions as no President has previously used
IEEPA to impose tariffs.
Although IEEPA has never previously been used to impose tariffs, in 1971, former President Richard M.
Nixon used the similarly worded Trading with the Enemy Act of 1917 (TWEA), upon which IEEPA was
based, to impose a 10% tariff on all imports into the United States in response to a monetary crisis.
President Nixon’s Emergency Tariff
On August 15, 1971, President Nixon issued Proclamation 4074, in which he declared a national
emergency and imposed a 10% ad valorem supplemental duty on all dutiable articles imported into the
United States. That evening, in a televised address to the nation, President Nixon outlined his new
economic policy, the targets of which were unemployment, inflation, and international speculation. He
addressed the supplemental duty specifically:
I am taking one further step to protect the dollar, to improve our balance of payments, and to increase
jobs for Americans. As a temporary measure, I am today imposing an additional tax of 10% on
