"On March 8, 2018, President Trump issued two proclamations imposing duties on U.S. imports of certain steel and aluminum products, using presidential powers granted under Section 232 of the Trade Expansion Act of 1962. Section 232 authorizes the President to impose restrictions on certain imports based on an affirmative determination by the Department of Commerce (Commerce) that the targeted products are being imported into the United States 'in such quantities or under such circumstances as to threaten to impair the national security.' Section 232 investigations and actions are important for Congress as the Constitution gives it primary authority over international trade matters. In the case of Section 232, Congress has delegated the President broad authority to impose limits on imports in the interest of U.S. national security. The statute does not require congressional approval of any presidential actions that fall within its scope. In the Crude Oil Windfall Profit Tax Act of 1980, however, Congress amended Section 232 by creating a joint disapproval resolution provision under which Congress could override presidential actions in the case of adjustments to petroleum or petroleum product imports."
CRS Report for Congress, R45249