Section 232 National Security Tariffs

Section 232 of the Trade Expansion Act of 1962, codified at 19 U.S.C. § 1862, authorizes the President to impose tariffs or quotas on imports that threaten to impair national security. Unlike Section 122's temporary emergency measure, Section 232 tariffs have no statutory expiration — they remain in effect indefinitely until the President modifies or removes them by proclamation.

The current Section 232 tariff structure covers seven dutied product categories: steel products (50%), aluminum products (50%), copper semi-finished products (50%), automobiles and auto parts (25%), softwood lumber (10%), advanced semiconductors (25%), and — added in late 2025 — medium and heavy commercial trucks and their parts (25%, with buses at a separate 10% tier). These rates were substantially increased in 2025, with steel, aluminum, and copper elevated to 50% from earlier rates of 25%. Separately, commercial aircraft, jet engines, and aircraft parts were investigated under Section 232 in July 2026, but no tariff was imposed — a 180-day negotiation window is under way instead of a duty.

The national security rationale for Section 232 rests on Commerce Department investigations finding that imports threaten domestic industrial capacity in sectors deemed critical to defense and critical infrastructure. Steel and aluminum are foundational to military hardware, shipbuilding, and defense construction. Automobiles and their supply chains support military vehicle manufacturing. Semiconductors underpin modern defense electronics, communications, and weapons systems. The Commerce Department findings under Section 232 are broad enough to justify tariffs across all countries, not just traditional adversaries.

Section 232 products are a critical exception within the broader tariff stacking formula. Because these products face their own dedicated tariff layer at Section 232 rates, they were excluded from the Section 122 global surcharge while it was in force, and remain excluded from the forced-labor Section 301 duty that backfilled it after the July 24, 2026 lapse. An importer of steel from Germany pays the MFN base rate (approximately 0%) plus the Section 232 rate of 50% — never 50% Section 232 plus Section 122's historical 10% rate, and never 50% Section 232 plus today's forced-labor duty. This exclusion prevents double-counting of national security tariffs, so steel and aluminum importers face substantial duties either way, unaffected by the Section 122 lapse on July 24, 2026.

Section 232 of the Trade Expansion Act of 1962, codified at 19 U.S.C. § 1862, provides the statutory framework for the national security tariffs. The law requires the Secretary of Commerce to investigate whether imports of a specific article "are being imported in such quantities or under such circumstances as to threaten to impair the national security." If the Secretary finds such a threat, the President has discretion to "take action, and for such time as he deems necessary, to adjust the imports of such article."

The broad presidential discretion under Section 232 has been the subject of significant litigation. In 2019, the Federal Circuit upheld the constitutionality of Section 232 steel and aluminum tariffs in American Institute for International Steel v. United States, holding that Congress properly delegated authority to the President in this national security context. Subsequent challenges in the Court of International Trade have generally been unsuccessful in challenging the scope of Section 232 proclamations.

The most recent major Section 232 proclamations significantly elevated rates. Steel and aluminum were raised from 25% to 50% effective June 4, 2025, following a Commerce Department investigation finding that increased imports had undermined the effectiveness of the 2018 tariffs at maintaining domestic steel and aluminum capacity at nationally security-sufficient levels. Automobiles were added to Section 232 in April 2025 at 25%, based on a finding that domestic auto manufacturing capacity was insufficient to meet defense and critical infrastructure needs. Semiconductors were added in January 2026 at 25%, reflecting findings about advanced chip supply chain vulnerabilities.

Section 232 tariffs apply regardless of the origin country — they are global measures, not targeted at specific trading partners. All countries face the same Section 232 rates unless specifically exempted by presidential proclamation. Canada, Mexico, and USMCA partners face Section 232 on non-qualifying goods; USMCA-qualifying steel and aluminum benefit from specific exemptions negotiated as part of the USMCA supplemental agreements.

The current Section 232 tariff rates as of 2026 are the highest in the program's history. Steel and steel products (HTS Chapters 72 and 73) face a 50% tariff, elevated from 25% on June 4, 2025. Aluminum and aluminum products (HTS Chapter 76) face the same 50% rate, also elevated June 4, 2025. Copper semi-finished products (primary HTS Chapter 74 items) face 50% since June 2025.

Automobiles and light trucks (principally HTS 8703) face 25% since April 3, 2025. Auto parts (selected HTS Chapter 87 subheadings) face the same 25% rate. The auto tariffs were designed to encourage domestic vehicle manufacturing and protect the domestic auto industrial base.

Softwood lumber and timber products (selected HTS Chapter 44 subheadings) face 10% under Section 232, a rate lower than metals reflecting lumber's different role in the national security calculation. The lumber tariff adds to any existing softwood lumber countervailing and antidumping duties, which have been in place under a separate trade remedy investigation.

Advanced semiconductors (selected HTS 8541 and 8542 subheadings covering logic chips, memory, and advanced packaging) face 25% since January 15, 2026, targeting advanced chips from Taiwan, South Korea, and other chip-producing countries. The semiconductor tariff creates particular complexity for technology importers who may find their products affected by both Section 232 and Section 122 considerations, with the s232Exempt flag in the product data confirming Section 232 treatment for semiconductors.

Medium- and heavy-duty commercial trucks and their parts (core HTS 8704) face 25% since November 1, 2025 under Proclamation 10984. This Section 232 duty is additive on top of the pre-existing 25% MFN "chicken tax", and buses (HTS 8702) carry a separate 10% tier. Importantly, light-duty pickups classified under HTS 8704.21 are excluded from this new duty and continue to carry only the chicken tax; USMCA-qualifying trucks receive a content-based partial offset requiring Secretary approval rather than an automatic exemption.

Commercial aircraft, jet engines, and aircraft parts were investigated under Section 232 in 2026, but — unlike the categories above — no tariff was imposed. Proclamation 11040 (July 2026) found a national-security threat yet directed a 180-day negotiation window instead of a duty, reserving the possibility of alternative remedies later. Aircraft therefore carry no Section 232 rate today; commercial aircraft remain generally duty-free under the WTO Civil Aircraft Agreement.

Patented pharmaceuticals and their associated ingredients carry a headline 100% rate under Proclamation 11020, staged from July 31, 2026 for the companies listed in the proclamation's Annex III and September 29, 2026 for all others. Four reduced tiers apply: 20% for companies whose onshoring plans the Secretary has approved, rising to 100% on April 2, 2030; 15% for Japan, the European Union, the Republic of Korea, and Switzerland and Liechtenstein jointly; 10% for the United Kingdom, reducing to zero to the extent required by any future US-UK pharmaceutical-pricing agreement; and 0% for orphan drugs, nuclear medicines, plasma-derived therapies, fertility treatments, cell and gene therapies, antibody drug conjugates, CBRN medical countermeasures and animal-health products, plus companies under a most-favored-nation pricing agreement until January 20, 2029. Where more than one rate could apply, the lowest governs. Crucially, this duty works differently from every other Section 232 rate on this page: it is MFN-INCLUSIVE. The Section 232 duty and the Column 1 rate together add up to the applicable tier — a ceiling, not a surcharge layered on top of MFN — unless the Column 1 rate is already higher, in which case only Column 1 applies. That clause does not apply to the United Kingdom. Generic pharmaceuticals and their associated ingredients, including biosimilar products, are expressly excluded.

It is important to note that Section 232 products are excluded from the Section 122 surcharge — they pay Section 232 rates instead of Section 122. This exclusion proved significant: when Section 122 lapsed on July 24, 2026, steel and aluminum importers saw no change in their tariff burden, because their costs are governed entirely by Section 232 — and S232 products are also excluded from the forced-labor Section 301 duty that backfilled the lapse for other goods.

Section 232 applies across steel, aluminum, copper, automobiles and parts, softwood lumber, advanced semiconductors, and — since late 2025 — medium/heavy commercial trucks and buses, covering a significant portion of US industrial imports (a separate aircraft investigation concluded in 2026 with no tariff imposed). Steel products encompass a broad range of flat-rolled, long, and tubular steel products classified in HTS Chapters 72 and 73. This includes hot-rolled coil, cold-rolled coil, galvanized sheet, structural shapes, pipes, and tubes. Steel downstream articles (products made from steel, like furniture, appliances, and industrial equipment) may also face downstream Section 232 duties in some cases.

Aluminum products under HTS Chapter 76 include primary aluminum ingots, aluminum sheet, foil, wire, bars, and extrusions. The 50% rate applies broadly across the chapter to both raw aluminum and semi-finished aluminum products. Some aluminum downstream articles in other HTS chapters are also covered.

Copper semi-finished products in HTS Chapter 74 include copper wire, rods, bars, sheets, plates, and tubes. The 50% rate was designed to protect domestic copper smelting and refining capacity. Copper ore and concentrate, which is imported for domestic smelting, has different treatment.

The automotive Section 232 covers passenger cars, SUVs, light trucks, and their component parts. The 25% rate applies to completed vehicles under HTS 8703 and to a defined list of auto parts under Chapter 87. For importers of automotive components, determining whether specific parts are covered requires reviewing the specific HTS classifications listed in the presidential proclamation.

The semiconductor Section 232 covers advanced logic chips, memory chips, and advanced packaging products. The HTS subheadings covered are primarily in 8541.10 through 8541.90 and 8542.31 through 8542.90. Standard discrete components and less advanced chips may not be covered, requiring verification of specific HTS classifications.

The pharmaceutical Section 232 is scoped to HTS Chapters 29 and 30 only, entered under HTSUS headings 9903.04.60 through 9903.04.69, which are mutually exclusive so an article falls under at most one of them. What decides whether an article is covered is patent status, not HTS classification: "patented pharmaceutical articles" are those subject to a valid, unexpired US patent and listed in the FDA's Orange Book or Purple Book, together with the active pharmaceutical ingredients and key starting materials for such articles. Generic articles — not under a valid unexpired patent and off exclusivity — are outside the action, as are biosimilars. Because two shipments of the same HTS heading can fall on opposite sides of that line, this calculator adds nothing for pharmaceuticals; none of the site's pharmaceutical categories carries a Section 232 flag, since patent status is not represented in the data model. Verify a specific article against the HTSUS headings above. US-origin pharmaceutical products returning to the country are not subject to the duty, and drawback is available.

Section 232 products interact with the broader tariff stacking formula in a specific way: Section 232 replaces Section 122 for covered products, and Section 232 itself is not replaced by higher bilateral deal rates for products that are both S232-covered and in a bilateral deal country.

The core rule is that Section 232-covered products face: MFN rate + Section 232 rate + Section 301 (if Chinese origin). The Section 122 layer is excluded entirely. This meant that when Section 122 lapsed on July 24, 2026, importers of steel, aluminum, copper, autos, lumber, and semiconductors saw no change in their total tariff burden — Section 232 continues unchanged, and these products are excluded from the forced-labor Section 301 duty as well.

For Chinese-origin Section 232 products, Section 301 can still stack on top of Section 232. A Chinese steel product faces MFN + 50% Section 232 + any applicable Section 301 rate for downstream steel articles. This represents some of the highest effective tariff rates in US import history. Chinese-origin steel pipes and tubes, for instance, can face total duties exceeding 75% when combining Section 232 and Section 301 rates.

Section 232 interacts simply with everything else, because it wins. A steel import from Japan faces MFN + 50% Section 232. Nothing else reaches it: Section 232-covered goods are excluded from the forced-labor Section 301 duty exactly as they were from Section 122, and the 15% Japanese reciprocal country rate that older analysis cites was terminated on February 20, 2026 and would not apply in any case because Section 232 (50%) exceeds either individually or combined. In practice, this means bilateral deal countries that export large amounts of steel to the US are not benefiting from their deal rates on those steel exports.

USMCA has a partial interaction with Section 232: USMCA-qualifying goods generally receive preferential treatment, but steel and aluminum from Canada and Mexico remain subject to Section 232 unless covered by specific steel and aluminum exemption agreements negotiated as part of the USMCA supplemental framework. Automotive products meeting USMCA rules of origin (75% North American content) may qualify for exemption from automotive Section 232 duties in certain circumstances.

Section 232 tariffs have no statutory expiration date — they continue indefinitely until modified or removed by presidential proclamation. This permanence distinguishes them sharply from Section 122, which lapsed July 24, 2026 after its 150-day limit. Importers of Section 232 products should plan around these tariffs as a long-term structural feature of their cost structure.

The most likely changes to Section 232 in the near term involve potential rate modifications rather than elimination. Domestic steel, aluminum, and auto industries have lobbied for maintaining or even increasing rates. Downstream users of steel and aluminum (construction, appliance, and auto parts manufacturers) have advocated for rate reductions or targeted exemptions. The administration faces ongoing pressure from both directions.

For the automobile sector, the potential impact of Section 232 on US automotive supply chains and vehicle prices has generated significant political attention. US automakers with North American supply chains are navigating between USMCA content requirements and Section 232 auto parts tariffs, with some parts facing tariffs at assembly even when vehicles qualify for USMCA treatment on final assembly.

The semiconductor Section 232 will be closely watched as US-Taiwan, US-South Korea, and US-Japan trade relationships evolve in 2026. Taiwan and South Korea are major chip exporters and have raised concerns about the semiconductor Section 232 in bilateral trade discussions. Any country-level exemptions for semiconductor allies would be significant departures from the current all-countries approach.

From a landed cost perspective, Section 232 tariffs represent the most structurally stable layer in the US tariff stack. Unlike Section 122 (lapsed July 24, 2026 and replaced by the forced-labor Section 301 duty), Section 232 rates are unlikely to change significantly in the near term. Importers of steel, aluminum, autos, copper, lumber, semiconductors, and commercial trucks should model their landed costs assuming current Section 232 rates remain in place for 2026 and beyond. Aircraft importers should monitor the 2026-2027 negotiation window, which could result in a future duty where none exists today.