Tariff Power & Authority
The Constitution places tariff and foreign-commerce power in Congress. Congress has delegated defined authorities for particular trade problems. This collection follows those delegations, their statutory triggers, institutional processes, limits, government records, and judicial review — including the current use of Section 338 of the Tariff Act of 1930 for certain goods of Canada.
What law authorizes the tariff?
A tariff may appear on an entry summary as a number, but behind that number is a chain of public authority.
The inquiry begins with Congress. What constitutional power is being exercised? What statute, if any, delegates authority to the Executive? What factual trigger must exist? Which agency develops the record? What limits did Congress impose? What may a court review?
The purpose of this collection is to make that chain visible.
Congress begins the tariff inquiry.
Article I gives Congress the power to lay and collect duties and to regulate commerce with foreign nations. Modern tariff statutes operate through authority Congress has enacted within that constitutional framework.
Read Article I at Congress.gov →Identify the constitutional source of federal tariff and foreign-commerce authority.
Determine whether Congress enacted a statute authorizing particular executive trade action.
Identify the trigger, process, duration, scope, findings, or other limits Congress placed on that authority.
Examine whether executive and agency action remained within the authority Congress actually granted.
Different problems. Different delegations.
These authorities should not be treated as interchangeable. Each begins with a different statutory purpose and produces a different administrative record.
Article I
The starting point. Congress possesses the constitutional authority from which the modern statutory tariff system is built.
- Source
- U.S. Constitution
- Institution
- Congress
- Library Question
- What power was delegated, and on what terms?
Section 201
A statutory safeguard process addressing serious injury or threat of serious injury to domestic industry from import competition.
- Principal Record
- USITC investigation and findings
- Executive Role
- Presidential safeguard action
- Core Question
- Did the statutory injury process support the action?
Section 232
A national-security trade authority built around a Commerce Department investigation into the effects of imports on national security.
- Principal Record
- Commerce investigation and report
- Executive Role
- Presidential action following statutory process
- Core Question
- What national-security finding supports the measure?
Section 301
Authority administered through the United States Trade Representative to enforce U.S. trade-agreement rights and respond to certain foreign acts, policies, or practices.
- Principal Record
- USTR investigation, findings and modifications
- Institution
- United States Trade Representative
- Core Question
- What foreign practice and statutory finding support the action?
Section 338
A tariff authority directed at specified discrimination or unreasonable and unequal impositions by a foreign country that disadvantage U.S. commerce. If the statutory findings and public- interest determination are made, the President may proclaim additional duties designed to offset the burden or disadvantage.
- Maximum Duty
- 50% ad valorem or its equivalent
- Statutory Timing
- Additional duties take effect no earlier than 30 days after proclamation
- Institutional Record
- Presidential findings and proclamation; USITC statutory monitoring and recommendation duty
- Current 2026 Use
- Canada — alcoholic beverages, dairy, and motor-vehicle-related measures
Section 122
A temporary statutory authority for import surcharges or quotas when specified international balance-of-payments problems require special import measures.
- Maximum Surcharge
- 15% ad valorem
- Statutory Period
- Up to 150 days absent congressional extension
- Core Question
- Are the statutory predicate and limits satisfied?
IEEPA
Emergency economic authority available after declaration of a national emergency involving an unusual and extraordinary threat originating substantially outside the United States.
- Principal Statute
- 50 U.S.C. §§ 1701–1702
- Traditional Focus
- Economic transactions and property interests
- Tariff Record
- See the Learning Resources decision collection
The statute defines the problem before it defines the remedy.
| Authority | Primary statutory problem | Institutional record | Important constraint |
|---|---|---|---|
| §201 | Injury from import competition | USITC investigation | Statutory injury and safeguard process |
| §232 | Imports affecting national security | Commerce Department investigation | National-security statutory framework |
| §301 | Trade-agreement rights and certain foreign practices | USTR investigation and findings | Statutory findings and trade-response framework |
| §338 | Foreign-country discrimination or unreasonable and unequal imposition disadvantaging U.S. commerce | Presidential findings and proclamation; USITC statutory monitoring and recommendations | Public-interest finding; offset nexus; maximum 50% additional duty; statutory 30-day minimum before collection |
| §122 | Fundamental international payments problems | Presidential proclamation and implementation record | Rate and duration limits |
| IEEPA | Unusual and extraordinary foreign-sourced emergency threat | Emergency declaration and executive actions | Powers must remain within the statute Congress enacted |
Statute, findings, proclamation, and entry implementation.
In July 2026, the President invoked Section 338 in three proclamations concerning Canadian alcoholic beverages, dairy, and motor-vehicle-related measures. Proclamation 11056 later moved the effective date to August 22, 2026.
CBP now implements the action through HTSUS headings 9903.03.12–9903.03.16. Headings .12–.14 carry a 50% Section 338 additional duty for the covered product lists; headings .15–.16 provide a 0% Section 338 rate for specified excluded categories. Other applicable duties, taxes, fees, antidumping or countervailing duties, and other trade remedies can continue to apply.
Source discipline: the proclamations contain presidential statutory findings and determinations. They should be identified as such rather than treated as independent judicial findings of fact.
Alcoholic Beverages
Presidential Section 338 findings and the covered Canadian-product tariff schedule for the alcohol-related action.
Open official proclamation → PROCLAMATION 11047 · 91 FED. REG. 46653Dairy
Presidential Section 338 findings concerning Canadian cheese tariff-rate-quota treatment and the resulting tariff schedule.
Open official proclamation → PROCLAMATION 11048 · 91 FED. REG. 46663Motor Vehicles
Presidential Section 338 findings concerning Canada's motor-vehicle tariff measures and the related covered-product schedule.
Open official proclamation → PROCLAMATION 11056 · 91 FED. REG. 54789Effective-Date Amendment
Suspended collection for three days and amended the effective date of Proclamations 11046–11048 to August 22, 2026.
Open official proclamation → CBP · CSMS #69606660 · AUGUST 21, 2026Section 338 Entry-Filing Guidance
CBP's operational instructions identify HTSUS 9903.03.12–9903.03.14 at 50%, the specified 0% Section 338 exclusion headings 9903.03.15–9903.03.16, entry sequencing, foreign-trade-zone treatment, drawback, and continued application of other duties and charges.
Open CBP implementation guidance → FCA · TRADE WAR WITH CANADASection 338 Legal Brief
Follow the Canada-specific legal record separating statutory predicates, presidential findings, implementation, and open questions for legal review.
Open Canada tariff-power page →Follow the chain.
Start with the statute
Identify the exact law claimed as the source of authority.
Find the trigger
Determine what factual condition Congress required before the authority could be exercised.
Find the record
Locate investigations, reports, findings, notices, proclamations, and agency materials.
Find the limits
Examine rate limits, time limits, procedural requirements, scope restrictions, exceptions, and review provisions.
Find the court record
Review how courts interpret the statute, jurisdiction, delegation, remedies, and executive compliance.
Follow authority into the live record.
Permanent Library pages explain the legal architecture. Fast-moving implementation and litigation belong in the current FCA record.
Section 338 · Canada
Follow the current use of Section 338, the three Canada proclamations, the August 22 effective date, and CBP's entry-level implementation.
Open Canada Section 338 Record → JUDICIAL / RECOVERY RECORDLearning Resources Decision
The Supreme Court record concerning use of IEEPA for the challenged tariff programs and the resulting refund framework.
Open Decision Record → HISTORICAL 2026 STATUTORY TRACKSection 122
The temporary 2026 balance-of-payments surcharge expired July 24. The Library retains the authority, implementation, and compliance record as historical law-in-operation.
Open Section 122 Record → LIVE DEVELOPMENTSCurrent Updates
Track new court orders, government positions, CBP implementation, tariff changes, hearings, and other time-sensitive developments.
View Current Record →Read the law itself.
Library explanations should lead back to the controlling public authority. These links open official constitutional, congressional, and government sources.
Name the authority.
Find the limits.
Read the record.
This Library page provides public-interest education concerning tariff law, statutory authority, government records, and related legal structure. It is not legal, customs, tax, accounting, investment, or financial advice. Authorities, executive actions, regulations, agency guidance, and judicial decisions should be checked for current status before they are relied upon in a specific matter.