The imposition of Section 301 tariffs on Chinese imports beginning in 2018 and Section 232 tariffs on steel and aluminum imports beginning in the same year fundamentally transformed the landscape of US trade policy in ways that continue to reverberate through global supply chains. These tariffs — imposed on hundreds of billions of dollars of annual imports and affecting virtually every sector of the US manufacturing economy — have forced companies to restructure supply chains, renegotiate contracts, raise prices, seek exemptions, and in many cases relocate production. The tariff environment has been further complicated by subsequent expansions, escalations, and modifications, and as of 2025-2026, US trade policy remains in a period of significant active change. Understanding the legal basis for these tariffs, their current scope, and the options available to affected businesses is essential for any US company engaged in international trade.

The Section 301 and Section 232 tariffs are legally and conceptually distinct, though they have operated in overlapping ways since 2018. Section 301 of the Trade Act of 1974 authorizes the President to take action against foreign country practices that are unfair, discriminatory, or burden US commerce, including imposing tariffs or other trade restrictions. Section 232 of the Trade Expansion Act of 1962 authorizes the President to adjust imports that threaten to impair US national security. Both statutes give the executive branch broad unilateral authority to impose tariffs without congressional approval, and both have been used aggressively by recent administrations as tools of trade policy that go well beyond their original legal frameworks.

Section 301 Tariffs on Chinese Imports

The Section 301 tariffs originated from the Trump administration’s 2018 finding that China’s practices related to technology transfer, intellectual property, and innovation were actionable under Section 301 of the Trade Act of 1974. In response to that finding, the US Trade Representative (USTR) imposed tariffs in four tranches on Chinese imports, covering virtually all goods imported from China. List 1 targeted $34 billion in Chinese goods, initially at a 25 percent rate. List 2 targeted an additional $16 billion in goods, also at 25 percent. List 3 targeted $200 billion in goods, initially at 10 percent and later raised to 25 percent. List 4A targeted $120 billion in goods at 7.5 percent, while List 4B was suspended.

The Biden administration maintained the Section 301 tariffs, declined to eliminate them despite calls from importers and economists, and in 2024 announced significant increases in tariff rates for specific strategic sectors: tariffs on Chinese electric vehicles were raised to 100 percent, tariffs on lithium-ion batteries were raised to 25 percent, tariffs on solar cells were raised to 50 percent, tariffs on steel and aluminum products from China were raised to 25 percent, and tariffs on semiconductors were raised to 50 percent. The Trump administration, returning to office in January 2025, further escalated Section 301 tariffs to 145 percent on virtually all Chinese goods as of April 2025, with subsequent modifications and potential negotiations ongoing. The tariff situation with China is extremely dynamic and requires constant monitoring.

For US importers, the Section 301 tariffs represent a significant addition to the landed cost of Chinese-origin goods, affecting cost competitiveness, pricing decisions, and make-or-buy analyses. Companies that source extensively from China have responded through a variety of strategies: shifting sourcing to alternative countries (Vietnam, India, Mexico, Thailand), investing in US domestic production, renegotiating supplier contracts, applying for tariff exclusions, and in some cases absorbing the cost increase. The most effective response depends on the company’s specific product mix, supplier relationships, lead time requirements, and competitive position.

Section 301 Exclusion Process

The USTR has administered exclusion processes for the Section 301 tariff lists, allowing importers to apply for product-specific exclusions that temporarily exempt particular products from the applicable tariff. Exclusions are granted on a product-by-process basis: the exclusion applies to a specific product description, not to a specific importer, meaning that any importer of goods meeting the product description can use the exclusion. The exclusion process requires the applicant to demonstrate that the product cannot be sourced from the United States or from third countries, that the tariff causes severe economic harm to the applicant, and that granting the exclusion would be in the public interest.

The exclusion process has been criticized for its inconsistency, opacity, and susceptibility to lobbying. Exclusions granted in one round have lapsed and not been renewed, forcing companies to reapply. The Biden administration renewed many exclusions and established new exclusion processes for specific lists, but the overall exclusion framework has remained uncertain. Companies relying on exclusions must monitor expiration dates closely and submit renewal applications in advance of expiration. The loss of a tariff exclusion without adequate warning can result in a sudden significant increase in import costs with no time to adjust the supply chain.

Section 232 Tariffs on Steel and Aluminum

The Section 232 tariffs were imposed by the Trump administration in 2018 following a Department of Commerce investigation that found that steel and aluminum imports threatened to impair US national security. The tariffs imposed a 25 percent tariff on steel imports and a 10 percent tariff on aluminum imports from most countries worldwide. Subsequently, various countries negotiated bilateral deals that resulted in their exemption from the Section 232 tariffs (the European Union, United Kingdom, Japan, and others) in exchange for alternative commitments on trade volumes or other concessions. Canada and Mexico were exempted from Section 232 tariffs under the USMCA framework.

In 2025, the Trump administration reinstated and expanded Section 232 tariffs, including reimposing tariffs on countries that had previously received exemptions and raising the aluminum tariff to 25 percent to match the steel tariff. The administration also imposed Section 232 tariffs on derivative steel and aluminum products — manufactured goods that contain steel or aluminum as a significant input, including auto parts, machinery, appliances, and construction products. These ‘downstream’ Section 232 tariffs dramatically expanded the scope of affected industries beyond traditional steel and aluminum users.

The Section 232 tariffs affect US manufacturers, construction companies, automotive producers, and any business that purchases steel or aluminum inputs, either directly as raw material or indirectly as components of purchased goods. Affected companies have responded by seeking domestic suppliers, qualifying alternative foreign suppliers in exempt countries, applying for product exclusion requests (the Section 232 process has its own exclusion mechanism), and adjusting product designs to reduce steel and aluminum content. The availability of domestic supply at commercially acceptable quality and lead times is often the binding constraint on supply chain adjustment, particularly for specialty steel grades and high-purity aluminum alloys.

Managing Tariff Exposure

Companies managing exposure to Section 301 and Section 232 tariffs should approach the problem systematically. The first step is a tariff impact assessment: an analysis of all imported products that are currently subject to elevated tariffs, quantifying the tariff cost per product, the total annual tariff burden, and the tariff cost as a percentage of product cost and selling price. This assessment provides the factual foundation for supply chain decisions and for prioritizing where tariff mitigation efforts will produce the greatest benefit. The second step is an evaluation of available mitigation strategies: product exclusion applications, supply chain diversification, first sale for export valuation, tariff engineering (redesigning products to avoid tariff subheadings), bonded warehouse and foreign trade zone utilization, and country of origin analysis to determine whether goods can qualify for tariff-free treatment under USMCA or other preferential programs. The third step is implementation and monitoring: executing the chosen strategies, monitoring for regulatory changes that affect their availability, and revisiting the analysis as conditions change. In a trade environment as volatile as the current one, tariff management is not a project that can be completed once — it must be maintained as a continuous business function.