Congress essentially delegated the authority to impose tariffs to the President via the Trade Act of 1974.Here's an informative article by the Brookings Institute, published on 19 January 2025:
Why does the executive branch have so much power over tariffs? Congress ceded authority to lay and collect customs duties to the executive branch in three acts:
- Reciprocal Trade Agreements Act of 1934 (RTAA)
- Trade Expansion Act of 1962
- The Trade Act of 1974
The RTAA authorized the president to negotiate bilateral, reciprocal trade agreements and to proclaim limited adjustments to tariff rates without congressional action.
The Trade Expansion Act of 1962 broadened this authority to include multilateral trade negotiations.
And The Trade Act of 1974 granted the president new authority to negotiate trade agreements and adjust tariffs, including the authority to take action against foreign countries that violate trade agreements or engage in practices that are deemed unfair and negatively affect U.S. commerce.