>The President is the only person able to make and break contracts wit foreign entities not the Congress, their charter is domestic.
Article I Legislative Branch
Section 8 Enumerated Powers
ArtI.S8.1 Overview of Congress's Enumerated Powers
Clause 1 General Welfare
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
https://constitution.congress.gov/browse/article-1/section-8/
Congressional and Presidential Authority to Impose Import Tariffs
The Constitution grants Congress the power to regulate foreign commerce, impose tariffs, and collect revenue.
Several statutes that may authorize the President or an executive agency to impose tariffs under various circumstances are currently in effect. This report includes a legal overview of six such statutes: Section 232 of the Trade Expansion Act of 1962; Sections 122, 201, and 301 of the Trade Act of 1974; Section 338 of the Tariff Act of 1930; and the International Emergency Economic Powers Act of 1977. These laws afford varying degrees of discretion to the President.
https://www.congress.gov/crs-product/R48435