Section 232 Becomes the Main US Tariff Tool: Metals at 50%, Autos, Chips, Drones and Polysilicon Next

Section 232 of the Trade Expansion Act of 1962 lets the Commerce Department investigate whether imports threaten national security and lets the President set tariffs if they do. Since the Supreme Court struck down the emergency tariffs in February 2026, it has become the administration’s main tariff tool. It now covers steel, aluminium, copper, cars, trucks, lumber, some semiconductors, patented drugs and drones, with polysilicon due in December.

The law suits the purpose. It needs no vote in Congress, has no time limit and sets no ceiling on rates. The courts have mostly deferred to the executive on what counts as national security.

What’s in place

Metals came first and were overhauled on 6 April 2026. Steel, aluminium and copper products pay 50%, with the tariff now applied across a wider list of products made from those metals.

Cars and parts pay 25%. Japan, the EU and South Korea negotiated 15% under their trade deals with Washington. Medium and heavy trucks, timber and lumber, and kitchen cabinets and furniture are covered by their own proclamations.

Advanced semiconductors were added from 15 January 2026, with relief for companies that commit to build chip plants in the US. Patented drugs followed in April at 100%, with lower rates for deal partners and exemptions for drugmakers with US manufacturing and pricing agreements.

On 3 September the President set tariffs on drones and drone parts: 100% on finished systems, 25% on components. On 4 December a 15% tariff on polysilicon, used in solar panels and chips, takes effect along with a minimum import price.

What’s pending

Commerce has open investigations into commercial aircraft and jet engines, wind turbines, robotics and industrial machinery, and medical equipment. Aircraft is the most delicate, because Europe and the US have kept aircraft trade largely tariff-free under past deals, and the EU’s 2025 agreement with Washington included aircraft and parts at zero.

The legal test

Importers have challenged the expanding reach of Section 232. In a case at the Court of International Trade, Express Fasteners argues that Commerce’s process for adding derivative products to the metal tariffs goes beyond what the statute allows. The court hasn’t ruled. Past appellate decisions have upheld wide presidential discretion under the law, so most trade lawyers expect the core tariffs to survive.

The role of Congress

The Constitution gives Congress power over tariffs, and it delegated much of it in laws like Section 232. Bills to require congressional approval of new national security tariffs have been introduced in both chambers since 2019 without passing. After the IEEPA ruling, Congress could have reclaimed the power. It hasn’t.

For the budget, Section 232 duties are a growing share of customs revenue, though neither Treasury nor CBO publishes a split by legal authority. For trading partners, the sector-by-sector approach means each new investigation reopens negotiations. Japan, Korea and the EU each secured caps at 15% on some sectors, and each has to watch every new proclamation for whether the cap applies.