Section 301 Tariffs Explained: How the US Trade Law Works
Section 301 tariffs explained: how USTR investigates unfair trade practices, the 2018 China tariffs and the six cases opened since 2025.
Section 301 tariffs explained in one line: Section 301 is the U.S. trade law that lets Washington investigate a foreign country’s trade practices and, if it finds them unfair, retaliate with tariffs. It was the legal basis for the tariffs on about $370 billion of Chinese goods imposed in 2018, and after the Supreme Court struck down tariffs imposed under emergency powers in 2026, it became a central tool again. This explainer covers how a Section 301 case works and where the open cases stand.
What Section 301 says
Sections 301 to 310 of the Trade Act of 1974, titled “Relief from Unfair Trade Practices,” are collectively called “Section 301,” according to a July 2026 Congressional Research Service (CRS) brief. Congress gave the Office of the U.S. Trade Representative (USTR) authority to investigate whether U.S. rights under a trade agreement are being denied, or whether a foreign government’s “act, policy, or practice” is “burdening or restricting U.S. commerce.” The law counts services and investment as commerce.
How a Section 301 investigation works
CRS describes five stages:
- Initiation. Anyone may petition USTR, which must decide within 45 days whether to open a case. USTR can also open one on its own and must publish notice in the Federal Register.
- Administration. A staff-level Section 301 Committee holds hearings and makes recommendations to the interagency Trade Policy Staff Committee.
- Consultations. USTR must request talks with the foreign government and, if they fail, seek formal dispute settlement under any governing trade agreement.
- Determination. Action is mandatory if USTR finds a trade-agreement violation or an “unjustifiable” practice that burdens U.S. commerce. It is discretionary if the practice is “unreasonable or discriminatory.” In cases not involving a trade agreement, USTR decides within 12 months.
- Action. USTR may impose tariffs or other import limits, suspend trade concessions, or reach a binding deal. It must favor tariffs if it chooses import restrictions, and it must invite public comment first.
Actions lapse after four years unless USTR receives a request for continuation and reviews the case. The statute does not set up any tariff exclusion process.
The China tariffs
After a 2017 investigation into Chinese practices on forced technology transfer and intellectual property, USTR imposed four rounds of tariffs in 2018, ranging from 7.5% to 25% on around $370 billion of imports, CRS reports. China retaliated with tariffs on $100 billion of U.S. goods. A 2024 four-year review kept the tariffs and raised some, such as those on electric vehicles.
Section 301 investigations in 2025 and 2026
The USTR’s list of investigations shows a sharp rise in new cases. As of CRS’s July 2026 update:
| Target and subject | Opened | Status (CRS, July 2026) |
|---|---|---|
| Brazil: digital trade, ethanol and other issues | July 2025 | Concluded June 2026; 25% tariff proposed |
| China: Phase One deal implementation | October 2025 | Ongoing |
| 16 economies: structural excess capacity | March 2026 | Ongoing |
| 60 economies: forced labor import bans | March 2026 | Concluded June 2026; 10%–12.5% tariffs proposed |
| Vietnam: intellectual property | May 2026 | Ongoing |
| Germany: pharmaceutical pricing | June 2026 | Ongoing |
CRS links the two March 2026 cases to the Supreme Court ruling that invalidated tariffs imposed under the International Emergency Economic Powers Act (IEEPA). It says USTR could use their findings to build “a regime of country-specific tariffs similar in scope” to the 2025 IEEPA tariffs.
What it means: Peter’s World analysis
Section 301 was written for targeted disputes, and for decades the United States used it mainly to build World Trade Organization cases, according to CRS. Running dozens of economies through it at once turns a case-by-case remedy into a broad tariff system, with a key difference from IEEPA: each step has a public record, comment periods and a statutory test, which could make the results harder to challenge in court. That shift also hands the policy question back to Congress, which CRS notes could weigh whether this use matches what lawmakers intended when they granted the authority.
For daily coverage, see the trade war news hub.
Sources
- Congressional Research Service: Section 301 of the Trade Act of 1974 (IF11346, July 2, 2026)
- Office of the U.S. Trade Representative: Section 301 Investigations
Related coverage
- IEEPA Tariff Refunds: $126B Paid, Court Certifies Class for Rest
- Trade War Oct 24, 2026: USTR Proposes Longer China Port-Fee Pause
- Trade War Weekly Roundup: Investment Rules, China Export Curbs
