Who can impose tariffs now?

Congress writes the tariff laws, but presidents can still impose tariffs when Congress has already handed them that power in statute. (congress.gov) The Constitution puts duties and foreign commerce in Congress’s hands under Article I, Section 8. Congress has since delegated narrower tariff powers through laws including Section 232 of the Trade Expansion Act of 1962 and Sections 122, 201, 301, and 338 of later trade statutes. (congress.gov) Those laws do not work the same way. Section 232 lets a president restrict imports after a Commerce Department investigation finds they threaten national security, while Section 301 runs through the U.S. Trade Representative to answer foreign trade practices the United States says are unfair. (congress.gov; ustr.gov) The biggest recent limit came from the Supreme Court on February 20, 2026. In *Learning Resources v. Trump*, the justices held 6-3 that the International Emergency Economic Powers Act, or IEEPA, does not authorize the president to impose tariffs. (supremecourt.gov) That ruling knocked out the emergency tariffs Trump had tied to fentanyl trafficking and to the April 2025 “reciprocal” tariff plan. The Court’s syllabus says those actions included 25% duties on most Canadian and Mexican imports, 10% duties on most Chinese imports, and a baseline tariff of at least 10% on imports from all trading partners. (supremecourt.gov) The decision did not erase every presidential tariff already on the books. Congress’s own research service says Section 232 and Section 301 remain active sources of delegated authority, and courts have generally upheld tariff statutes themselves against constitutional attack. (congress.gov) That is why presidents still have room to act even after losing the IEEPA fight. A February 12, 2026 Congressional Research Service brief says the second Trump administration had already launched 12 Section 232 investigations, completed five, and imposed tariffs in four of those cases. (congress.gov) One example is autos. A March 26, 2025 proclamation, published April 3, 2025, imposed a 25% tariff on imported automobiles and certain auto parts under Section 232 after reviving a 2019 Commerce finding that those imports threatened national security. (federalregister.gov) Section 301 is still in play too. The U.S. Trade Representative’s current investigations page lists live cases opened on March 12, 2026 over forced-labor enforcement, March 11, 2026 over manufacturing excess capacity, October 24, 2025 over China’s Phase One commitments, and April 17, 2024 over China’s maritime, logistics, and shipbuilding sectors. (ustr.gov) Congress can change this balance if it wants to. Congressional Research Service reports say lawmakers are weighing whether to curb, modify, or tighten oversight of Section 232 and other delegations as courts and presidents keep testing how much tariff power the White House can use without a new vote on Capitol Hill. (congress.gov; congress.gov) Trade partners have not treated the dispute as a purely domestic legal question. The European Commission said on May 8, 2025 that it was preparing possible countermeasures and World Trade Organization litigation over U.S. tariffs, and Canada’s finance department says it adopted retaliatory measures while negotiating with Washington. (ec.europa.eu; canada.ca) So the short answer now is split. Congress still owns the tariff power on paper, presidents still wield a large share of it through statutes Congress already passed, and courts are deciding where those statutes stop. (congress.gov; supremecourt.gov)