Navigating the New U.S. Tariff Landscape after the US Supreme Court IEEPA Ruling

A Practical Reference for Attorneys and Clients

The U.S. trade enforcement environment has changed more in the past twelve months than in any comparable period in recent memory, and the pace of change has not slowed. A Supreme Court ruling in February 2026 invalidated the tariff framework that had defined U.S. trade policy throughout 2025, and the administration’s response has already produced new statutory authorities, a new global surcharge, and the broadest set of trade investigations ever launched under a single statute. For businesses importing into the United States — and for the attorneys advising them — a working understanding of where things stand today is essential. What follows is a plain-language overview of the statutes, agencies, and concepts most relevant to current practice.

Key Takeaways

• The Supreme Court held in February 2026 that IEEPA does not authorize tariffs. All IEEPA-based tariffs have been terminated, and importers who paid them have refund rights — roughly $160 billion across 53 million entries.
  
  
• A 10% global import surcharge under Section 122 replaced the IEEPA tariffs on February 24, 2026. This surcharge expires by statute on July 24, 2026 — 150 days from imposition — unless Congress acts.
  
  
• USTR launched the broadest Section 301 investigations in history in March 2026, targeting 16 economies for manufacturing overcapacity and 60 economies for failure to enforce forced labor bans. New country-specific tariffs are expected before the Section 122 expiration date.

• Section 232 tariffs (steel, aluminum, copper, autos) and existing Section 301 tariffs on Chinese-origin goods were entirely unaffected by the ruling and remain in full force.

• Importers should conduct a comprehensive tariff exposure review now, preserve all documentation related to prior IEEPA payments, and prepare for significant further changes before July 2026.

The Principal Tariff Authorities

Section 301 of the Trade Act of 1974 gives the U.S. government authority to impose tariffs against unfair foreign trade practices, including intellectual property theft and forced technology transfer. Existing Section 301 tariffs on Chinese-origin goods — ranging from 7.5% to over 100% depending on product category — remain fully in force and were entirely unaffected by the recent Supreme Court ruling. Separately, USTR launched two waves of new Section 301 investigations in March 2026: one targeting 16 economies for manufacturing overcapacity (including several ASEAN members) and one targeting 60 economies for failure to enforce forced labor bans (including all ASEAN states). These investigations are designed to produce new, country-specific tariffs in advance of July 2026 and represent the most significant pending development in U.S. trade law at the time of this publication.

Section 232 of the Trade Expansion Act of 1962 authorizes tariffs where imports threaten U.S. national security. Steel and aluminum tariffs were raised to 50% on June 4, 2025 and apply globally regardless of country of origin. Copper was added under Section 232 as well, also at 50%, covering semi-finished copper products and key derivatives. Automobiles and auto parts face a separate 25% Section 232 tariff imposed in April 2025. Section 232 tariffs were entirely unaffected by the February 2026 Supreme Court ruling and remain in full force. Importantly, goods already subject to Section 232 are exempt from the new Section 122 global surcharge — these tariffs do not stack.

Antidumping (AD) and Countervailing Duties (CVD) are distinct from the above and, in many cases, represent the greatest tariff exposure a business can face. Antidumping duties apply when goods are sold in the U.S. below fair value; countervailing duties offset the effect of foreign government subsidies. Both are product- and company-specific, determined through formal government investigations. Combined AD/CVD rates exceeding 100% are not uncommon, and they can apply on top of Section 232 duties and the Section 122 surcharge — making accurate tariff stacking analysis essential.

The Forced Labor Dimension

The Uyghur Forced Labor Prevention Act (UFLPA) establishes a legal presumption that goods produced wholly or in part in the Xinjiang Uyghur Autonomous Region of China are made with forced labor and are therefore inadmissible into the United States. Rebutting this presumption requires clear and convincing evidence of end-to-end supply chain traceability, including raw material sourcing. Shipments that cannot meet this standard are subject to detention, exclusion, or seizure. This is one of the most operationally demanding compliance obligations facing importers — particularly those with ASEAN-based production that relies on Chinese inputs. The Section 301 forced labor investigation launched in March 2026, which targets all 10 ASEAN states, adds a parallel statutory layer that importers should monitor closely.

Enforcement: CBP and EAPA

U.S. Customs and Border Protection (CBP) is responsible for enforcing customs laws at the border, and its enforcement posture has grown considerably more active. Importers encountering a CF-28 (Request for Information) or CF-29 (Notice of Action) from CBP should treat either as a serious compliance event requiring prompt attention from qualified counsel.

The Enforce and Protect Act (EAPA) is CBP’s principal tool for investigating duty evasion through transshipment, deliberate misclassification, or undervaluation. EAPA investigations can result in retroactive duty assessments and substantial penalties, and are frequently initiated by competitor petitions. For ASEAN-based suppliers, the transshipment dimension is particularly significant given ongoing CBP scrutiny of Chinese-origin goods routed through the region to access the U.S. market at lower duty rates.

The IEEPA Ruling and Its Aftermath

The single most consequential development in U.S. trade law in recent years occurred on February 20, 2026, when the Supreme Court issued its 6-3 decision in Learning Resources, Inc. v. Trump (607 U.S. ___ (2026)), holding that the International Emergency Economic Powers Act (IEEPA) does not authorize the President to impose tariffs. Chief Justice Roberts, writing for the majority, concluded that IEEPA’s authority to ‘regulate importation’ does not extend to tariff-setting — a power the Constitution assigns to Congress.

The practical consequences were immediate. On the same day as the ruling, the President issued an executive order terminating all IEEPA-based tariffs, effective February 24, 2026. The administration simultaneously invoked Section 122 of the Trade Act of 1974 to impose a 10% global import surcharge on virtually all goods from all countries, effective the same date. The administration has announced plans to raise the Section 122 rate to 15% — the statutory maximum — though formal executive action implementing the increase remained pending as of the date of this publication.

Section 122 is a narrower authority than IEEPA in important respects: it caps tariffs at 15% and limits their duration to 150 days, meaning the current surcharge expires on July 24, 2026 unless Congress acts to extend it. To establish longer-term authority before that deadline, USTR launched sweeping Section 301 investigations in mid-March 2026, targeting 16 economies for manufacturing overcapacity and 60 economies for failure to enforce forced labor bans. The administration has signaled its intention to conclude these investigations and impose new country-specific tariffs before July 24.

Two additional implications are worth flagging for clients. First, Section 232 tariffs and existing Section 301 tariffs on Chinese-origin goods were entirely unaffected by the ruling and remain in full force. Second, the IEEPA ruling creates refund rights for importers who paid tariffs under IEEPA authority — roughly $160 billion collected across approximately 53 million entries. The Court of International Trade has ordered CBP to process these refunds, though the mechanics and timing remain under active litigation. Companies with material IEEPA tariff exposure should take immediate steps to preserve refund rights, including: retaining all entry summaries, payment records, and broker documentation for the period of IEEPA tariff application; confirming with their customs broker that all affected entries have been identified and flagged; and monitoring Court of International Trade proceedings for filing deadlines or procedural requirements that may affect eligibility. Given the scale of the refund pool and the likelihood of administrative complexity, early engagement of qualified trade counsel is strongly advisable.

De Minimis

De minimis (Section 321 of the Tariff Act of 1930), the longstanding provision allowing duty-free entry of shipments valued below $800, remains suspended. Following the IEEPA ruling, the President issued a separate executive order continuing the suspension under IEEPA’s non-tariff regulatory authority — a legal position that is being challenged in ongoing litigation. It is worth noting the inherent tension in this approach: the Supreme Court has now held that IEEPA does not authorize tariffs, and the administration’s reliance on the same statute’s non-tariff provisions to maintain the de minimis suspension may face heightened judicial skepticism as a result. For now, importers who built their U.S. market entry strategy around duty-free low-value shipments cannot rely on that approach, but should monitor the pending litigation closely, as a successful challenge could restore the $800 threshold.

Origin, Classification, and Tariff Stacking

Rules of Origin determine the country to which a product is legally attributed for tariff purposes, typically through a ‘substantial transformation’ analysis. As companies have shifted production out of China — including into ASEAN jurisdictions — CBP has grown increasingly skeptical of origin claims that appear designed primarily for tariff avoidance rather than genuine manufacturing relocation. Counsel should anticipate heightened scrutiny under the March 2026 Section 301 investigations, which directly target ASEAN manufacturing and raise the stakes for origin documentation across the region.

Tariff stacking — the cumulative application of multiple tariff regimes to the same product — is now a baseline feature of import compliance analysis. A single product could face Section 232 tariffs, existing Section 301 tariffs on Chinese inputs, the Section 122 global surcharge, and future Section 301 tariffs resulting from the March 2026 investigations — all simultaneously. Accurately mapping total landed cost exposure across all applicable regimes is the foundation of any serious compliance review.

By way of illustration: a Vietnamese-manufactured product incorporating Chinese-origin steel could face a 50% Section 232 tariff on the steel component, existing Section 301 tariffs on the Chinese inputs (rates varying by product category), and — if the March 2026 Section 301 investigations result in new country-specific tariffs on Vietnamese-origin goods — an additional layer on the finished product. Depending on the product and its inputs, effective combined rates well in excess of 75% are realistic. This underscores the importance of mapping total landed cost exposure across all applicable regimes before making sourcing or pricing commitments.

Questions Every Importing Client Should Be Prepared to Answer

Attorneys advising clients with U.S. import activity should ensure the following can be answered clearly, and with supporting documentation:

• What is being imported, and under what tariff classifications?
• Where are the products actually manufactured — not merely shipped from?
• Has any production been relocated out of China in the past 12 to 18 months, and can the origin claim be fully substantiated?
• Do the products involve steel, aluminum, copper, or other materials subject to Section 232?
• Can any part of the supply chain be traced to Xinjiang or entities on the UFLPA Entity List?
• Has the client received any CBP inquiries, including CF-28s, CF-29s, or detention notices?
• Are any products subject to existing or pending antidumping or countervailing duty orders?
• Has the client paid meaningful IEEPA tariffs? If so, have steps been taken to preserve refund rights?
• How will the client’s tariff exposure change if Section 301 investigations result in new country-specific tariffs by July 2026?
• If audited tomorrow, could the client fully demonstrate origin, value, and supply chain integrity?
• Does the client benefit from any preferential trade agreement with the United States (e.g., the U.S.-Singapore FTA), and has the legal basis for any applicable bilateral arrangement been affected by the IEEPA ruling?

Closing Observation

The framework described above reflects U.S. tariff law as of March 30, 2026 — but that framework is moving faster than at any point in recent decades. The IEEPA ruling, the Section 122 global surcharge, the March 2026 Section 301 investigations, the ongoing refund proceedings, and the uncertain legal status of bilateral trade deals negotiated under now-invalidated IEEPA authority all create real uncertainty that clients need to plan for rather than wait out. We encourage colleagues to treat the questions above as the basis for an active compliance review, not a one-time checklist.

For questions, client-specific analysis, or to arrange a preliminary tariff exposure assessment, please contact the DFDL Trade & Customs Practice.

APPENDIX: U.S. TARIFF RATES ON ASEAN — CURRENT REFERENCE TABLES

As of March 30, 2026  |  For attorney and client reference only

Important: The IEEPA-based reciprocal tariff rates that applied from August 2025 through February 23, 2026 are no longer in effect following the Supreme Court’s ruling in Learning Resources, Inc. v. Trump (Feb. 20, 2026). All ASEAN countries now face the same 10% Section 122 global surcharge, effective February 24, 2026. Sector-specific Section 232 rates remain in effect and do not stack with Section 122. New Section 301 investigations opened in March 2026 may produce new country-specific tariff rates by July 24, 2026. This area of law is evolving rapidly; all rates should be verified against current CBP guidance before client advice is given.

TABLE 1: U.S. Tariff Rates by ASEAN Country — Prior IEEPA Rates and Current Status

Country	Prior IEEPA Rate (Aug.2025 – Feb.23,2026)	Current Rate (Sec.122, eff. Feb.24,2026)	Section 301 Investigation Status (March 2026)	Key Export Sectors & Notes
Singapore	10%	10%	Overcapacity (Mar.11) Forced Labor (Mar.12)	Received baseline rate throughout; U.S.-Singapore FTA in place; U.S. runs trade surplus with Singapore. Key exports: semiconductors, pharmaceuticals, refined petroleum. Many key exports are exempt from reciprocal tariff measures.
Vietnam	20%	10%	Overcapacity (Mar.11) Forced Labor (Mar.12)	Highest prior IEEPA rate among major ASEAN trading partners, reflecting a $178B goods trade surplus with the U.S. in 2025. Rate now effectively 10% under Section 122. Key exports: electronics, textiles, footwear, furniture. Now among the U.S.’s top chip suppliers.
Indonesia	19%	10%	Overcapacity (Mar.11) Forced Labor (Mar.12)	U.S.-Indonesia reciprocal trade agreement signed Feb. 19, 2026 — one day before the IEEPA ruling — placing its legal foundation in immediate uncertainty. Key exports: coal, palm oil, textiles, footwear.
Malaysia	19%	10%	Overcapacity (Mar.11) Forced Labor (Mar.12)	Prior bilateral deal included rare-earth cooperation clause and 0% commitments on select goods. Legal status of the deal uncertain post-IEEPA ruling. Key exports: electronics, semiconductors, palm oil, rubber.
Thailand	19%	10%	Overcapacity (Mar.11) Forced Labor (Mar.12)	Prior framework included Thailand removing duties on 99% of U.S. goods. Legal basis now uncertain. Higher U.S. trade exposure than most ASEAN peers. Key exports: autos/parts, electronics, agriculture.
Philippines	19%	10%	Forced Labor (Mar.12) (Not in overcapacity list)	Prior rate raised from initial 17% to 19% under IEEPA. Not named in March 11 overcapacity investigation. Key exports: electronics, semiconductors, agricultural goods.
Cambodia	19%	10%	Overcapacity (Mar.11) Forced Labor (Mar.12)	Prior rate fell from original 49% following bilateral deal. Garment sector most exposed; forced labor scrutiny elevated. Key exports: garments, footwear, agriculture.
Brunei	25%	10%	Forced Labor (Mar.12) (Not in overcapacity list)	No bilateral deal was reached under IEEPA. Rate now at 10% alongside all other ASEAN countries under Section 122. Key exports: petroleum, natural gas.
Myanmar	40%	10%	Forced Labor (Mar.12) (Not in overcapacity list)	Among the highest IEEPA rates globally. Civil conflict limited negotiating capacity throughout 2025. Key exports: garments, agricultural goods.
Laos	40%	10%	Forced Labor (Mar.12) (Not in overcapacity list)	Among the highest IEEPA rates globally. Minimal U.S. export exposure limited negotiating urgency. Key exports: mineral resources, hydropower.
Timor-Leste	10%	10%	Timor-Leste not named in either investigation	Received baseline rate throughout. Minimal bilateral trade volume with the U.S. Key export: petroleum.

Sources: Learning Resources, Inc. v. Trump, 607 U.S. ___ (Feb. 20, 2026); USTR (March 11-12, 2026); East Asia Forum (Jan. 2026); Lowy Institute (2025); Sidley Austin LLP (Nov. 2025); DFDL (Nov. 2025); Al Jazeera (Jan. 2026); Holland & Knight (Feb. 2026); White & Case (March 2026).

TABLE 2: Sector-Specific U.S. Tariffs — Current Rates Applicable Across ASEAN

Tariff Authority / Measure	Current Rate	Scope, Status & Notes
Section 232 – Steel	50% (global)	Increased from 25% to 50% on June 4, 2025. Applies globally regardless of country of origin. Entirely unaffected by the February 2026 IEEPA ruling. Goods subject to Section 232 are exempt from the Section 122 global surcharge (the two do not stack). Note: UK steel receives 25% under the U.S.-UK Economic Prosperity Deal; Russian aluminum carries 200%.
Section 232 – Aluminum	50% (global)	Increased from 25% to 50% on June 4, 2025. Applies globally regardless of country of origin. Unaffected by the IEEPA ruling. Same non-stacking rule applies with Section 122. Section 232 scope has also been significantly expanded to cover derivative products.
Section 232 – Copper	50% (global)	Section 232 investigation completed. 50% tariff now applies to semi-finished copper products and copper-intensive derivatives from all countries. Fully in force and unaffected by the IEEPA ruling. Relevant for ASEAN exporters of copper-intensive products.
Section 232 – Automobiles and Auto Parts	25% (global)	Effective April 3, 2025. Applies globally. Excluded from IEEPA reciprocal tariff framework and from the Section 122 global surcharge. Directly relevant to Thailand, which is one of the region’s leading auto exporters.
Section 122 – Global Surcharge	10% (possibly 15%)	Imposed February 24, 2026 as the immediate replacement for invalidated IEEPA tariffs. Applies to virtually all imports from all countries. Does NOT stack on top of Section 232 tariffs – goods already subject to Section 232 are exempt. Expires July 24, 2026 (150-day statutory limit) unless Congress extends. Administration has stated intention to raise rate to 15% (the statutory maximum); formal executive action implementing the increase remained pending as of March 30, 2026.
Section 301 – Chinese-Origin Goods (Existing)	7.5% – 100%+	Pre-existing tariffs on Chinese-origin goods remain fully in effect and were entirely unaffected by the IEEPA ruling. Rates vary significantly by product category. Highly relevant to ASEAN importers given deep China-ASEAN supply chain integration and ongoing transshipment scrutiny.
Section 301 – New Investigations (March 2026)	Pending; rates TBD	USTR initiated two waves of investigations on March 11-12, 2026. The first (16 economies, including Singapore, Indonesia, Malaysia, Cambodia, Thailand, and Vietnam) addresses manufacturing overcapacity across sectors including steel, electronics, automobiles, semiconductors, and solar modules. The second (60 economies, including all 10 ASEAN states) addresses failure to enforce forced labor bans. Comments due April 15; hearings in May. The administration has signaled its intent to finalize new country-specific tariffs before July 24, 2026 – the Section 122 expiration date.
AD/CVD (Product-Specific)	Varies; often 100%+	Product- and company-specific; can apply on top of Section 232 tariffs, Section 301 tariffs, and the Section 122 global surcharge. Unaffected by the IEEPA ruling. Multiple ASEAN countries face active or pending orders. This is frequently the highest single source of tariff exposure for specific products.
Section 232 – Semiconductors	Under investigation	Formal Section 232 investigation ongoing. Currently exempt from the Section 122 surcharge pending investigation outcome. Closely watched by major ASEAN chip exporters, particularly Malaysia, Vietnam, the Philippines, and Singapore.
Section 232 – Pharmaceuticals	Under investigation	Formal Section 232 investigation ongoing. Currently exempt from the Section 122 surcharge. Highly relevant to Singapore and Malaysia, where pharmaceuticals are a leading export category.

Note: Section 232 tariffs apply instead of (not in addition to) the Section 122 surcharge for covered goods. Section 301 tariffs on Chinese-origin goods stack with both. AD/CVD can stack on top of all applicable regimes. Total landed cost analysis must account for all applicable layers simultaneously.

*This Client Alert is for informational purposes only and does not constitute legal advice. Specific advice should be sought for your particular circumstances.*

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