Policy Backgrounders

Section 232 Tariff Investigations and Public Comments

June 16, 2025

As the status of the Administration’s tariffs authorized under the International Emergency Powers Act (IEEPA) faces ongoing legal challenges, other authorities, such as those under Section 232 of the Trade Expansion Act of 1962, could become increasingly important. This Backgrounder explains these authorities and trends in business comments on current Section 232 investigations.

• Section 232 of the Trade Expansion Act of 1962 provides the President broad authority to impose restrictions on imports determined to threaten US national security. While it has existed for over fifty years, it has become increasingly important in recent years.
• Both the first and second Trump Administrations have used this authority to impose wide-ranging tariff strategies for strategically sensitive sectors.
• In response to seven new investigations initiated this year, industry stakeholders generally support strengthening domestic capabilities but advocate targeted, incentive-based strategies rather than sweeping tariffs that could undermine existing supply chains and increase costs for consumers.
• Ongoing investigations initiated this year may result in new import restrictions, including tariffs. Businesses should also prepare for additional Section 232 investigations, especially in sensitive industries.

Introduction

The Administration has sought to employ authorities under Section 232 of the Trade Expansion Act of 1962, initiating investigations in critical industries that impact trade and the broader economy. As the status of the Administration’s reciprocal tariffs is in question because of litigation questioning the legality of the justifications for the tariffs, other authorities may become increasingly important for future trade policy.

Process

Section 232 of the Trade Expansion Act of 1962 provides the President the authority to restrict imports based on an affirmative determination by the Department of Commerce after investigation that the product “is being imported into the United States in such quantities or under such circumstances as to threaten to impair the national security [.]” The Secretary of Commerce must initiate an investigation through self-initiation, upon the request of another U.S. Department or agency, or by petition from an interested external party (including Congress). This initiation begins a 270-day timeline in which Commerce investigates the claims of the request, consulting with other government agencies and possibly holding public hearings. The scope of the investigation can be expansive to include domestic production capacity, national defense implications, potential employment and unemployment impact, government revenues, and other considerations; there is no specific statutory definition for “national security.” This lack of a clear definition leads to ambiguity and provides the Executive Branch with broad authority.

The investigation concludes with report to the President, determining whether the subject of the investigation meets the criteria outlined by the statute to “threaten to impair” U.S. national security and recommending action or inaction based on the findings. The President then has 90 days to respond to the findings and determine any necessary action to address the threat to impair national security, including but not limited to Commerce’s recommendations. The President then has 15 days to implement the action and 30 days to submit a written explanation informing Congress of the action or inaction and publish the findings in the Federal Register.

Historical Use

The first Section 232 investigations began in the 1960s, concerning imports of manganese and chromium ferroalloys at the request of the Manufacturing Chemists Association (now the American Chemistry Council). The investigation resulted in a negative determination. The first positive determination did not occur until 1973, when the Chairman of the Oil Policy Committee under President Nixon requested an investigation into the import of crude oil and petroleum imports, resulting in the introduction of import licenses, quotas, and investments in domestic production for the oil industry.  Since then, the authority has been invoked over 40 times, resulting in positive determinations 14 times, termination twice, and negative determinations 16 times. Of the 14 positive determinations, only nine resulted in Presidential action in the form of tariffs or other trade restrictions.

There has been a clear partisan divide regarding use of the statute. Investigations under Presidents Johnson and Carter often concluded with negative determinations or were resolved without imposing trade measures. President Obama did not employ Section 232 at all. President Biden, while inheriting ongoing 232 actions, did not to initiate any new investigations.

In contrast, Republican Presidents have historically demonstrated a more assertive posture in utilizing this authority. Earlier Republican Administrations, including that of Ronald Reagan, invoked the statute, albeit with a narrower focus tied more directly to Cold War-era industrial and defense concerns. In President Trump’s first term, Section 232 use reached new heights; he markedly expanded both the frequency and scope of investigations. His administration employed Section 232 not only in contexts of traditional national security contexts such as steel and aluminum but also in sectors such as automotive manufacturing and semiconductors, using a rationale of economic security.

Exemptions and Exclusions

The President also maintains the authority to grant exemptions from trade measures. Typically, these are country-level exemptions, considering a wide range of economic and geopolitical factors. While a President can announce country-level exemptions at the onset of Section 232-related actions, recent actions and subsequent relief have come after negotiations. For example, for the 2018 global tariffs on steel and aluminum imports, President Trump granted Mexico and Canada an exemption after negotiations resulted in the two countries dropping retaliatory tariffs and agreeing to a measures to address unfair trade practices on related goods in North America.

In contrast, there is little historical precedent for granting exclusions for affected firms. The 2018 steel and aluminum tariffs provide the most extensive example. The Department of Commerce managed the exclusions process through its Bureau of Industry and Security (BIS), accepting requests from parties seeking exclusions from the required actions so long as they could prove that the imported good “not to be produced in the United States in a sufficient and reasonably available amount or of a satisfactory quality or based upon specific national security considerations.”  As of February 7, 2021, Commerce received 288,021 exclusion requests, 260,450 for steel and 27,571 for aluminum. Of those, the agency granted 170,084 exclusions and denied 59,134, with 44,325 exclusion requests rejected or withdrawn. A recent study of the process found that political interests and lobbying may have factored into these decisions.

The intense public interest in the exclusions process, along with Congressional scrutiny, resulted in the Department of Commerce updating the process. Although Commerce is no longer taking requests on these duties, strong exclusion petitions must adhere to the submission requirements on the BIS website. Should new actions restricting imports result from ongoing investigations, the exclusions process may follow a similar process.

Ongoing Section 232 Investigations

This year, the President has initiated seven Section 232 investigations that remain ongoing into a range of strategically sensitive sectors: timber and lumber, critical minerals, pharmaceuticals, commercial aircraft, semiconductors, copper, and trucks.

Timber and Lumber

Initiated on March 1. The order specifically recognizes that despite having a high practical production capacity for softwood consumption, the Administration is concerned that the US remains a net importer of lumber. Nearly 300 public comments indicated a high level of industry engagement that stressed the strategic necessity of domestically sourced timber for housing, disaster recovery, and defense-related construction. Organizations, including forestry groups and wood product manufacturer associations, emphasized protecting American workers and the importance of rural economic sustainability. While industry groups have advocated tariffs or quotas, many also stressed targeted approaches, such as strengthening federal procurement preferences and better forest management in favor of domestic production capacity.

Copper

Initiated on March 10 by Executive Order and covers raw materials, refined copper, and derivative products. Public comments generally supported strengthening domestic supply chains, but most stakeholders urged a cautious and targeted approach given copper’s role as a component in defense applications, infrastructure, energy, and technology. Industry groups mostly advised against tariffs, recognizing that the relationships with trading partners such as Peru, Chile, and Canada would be undermined and raise costs for downstream industries. Several groups also shared the need to support domestic mining, labor protection, and maintain high environmental standards to remain globally competitive.

Pharmaceuticals

Commerce launched an investigation into pharmaceuticals, pharmaceutical ingredients, and derivative products on April 1. The public comment period included nearly 1,000 comments focused on supply chain resilience and emphasizing avoiding disruptions to the generic drug market. Major health care industry associations dominated the public comments, with detailed commentary opposing tariffs on imported Active Pharmaceutical Ingredients and key starting materials. Many comments warned that tariffs would risk cost increases and exacerbate existing challenges in access for consumers, ultimately harming public health. Instead, groups recommended alternatives to help boost domestic production, including waiving FDA fees for drug manufacturers, subsidies for generics, and greater public-private coordination on procurement strategies.

Semiconductors and Manufacturing Equipment

Commerce initiated the investigation on April 1. Across over 200 public comments, there was broad consensus that semiconductors are vital to national security. Industry groups stressed the global nature of semiconductor supply chains and the strategic interdependence between US firms and allies such as Japan, South Korea, and Taiwan. In stressing this, stakeholders detailed the risks of imposing tariffs in a sector reliant on precision inputs, cross-border R&D, and just-in-time logistics, arguing that tariffs would disrupt downstream industries and complicate verification of origin of goods.

Critical Minerals and Derivative Products

Initiated on April 15 by Executive Order. Over 500 public comments demonstrated strong agreement on the importance of securing access to essential inputs including rare earth elements, lithium, and copper. Climate groups warned that broad trade restrictions could inhibit decarbonization and green industrial policy. Several trade associations, including the US Chamber of Commerce, advocated for a more targeted strategy that included expanding the US Geological Survey’s critical minerals list and fostering stable trade relationships with allies, rather than blanket tariffs impacting the wider industry and downstream products in the health care and tech sectors. Critical minerals are rising to prominence in ongoing trade negotiations between the US and several trading partners, including the European Union and China.

Trucks

Commerce initiated the investigation on April 22, citing potential national security threats from foreign competitors. This investigation received the most public comments of all (over 3,000) but the docket is not yet complete. An analysis of comments shared by various industry groups finds significant opposition to the investigation and potential tariffs, given the far-reaching role the trucking industry plays in the economy. Comments on this investigation may follow similar perspectives from the Section 232 investigation into autos from 2019, including opposition to potential tariffs from automakers and industry groups alongside support from labor union groups seeking protection for the domestic industry against what they consider unfair competition.

Commercial Aircraft and Jet Engines

The commercial aircraft and jet engines investigation was initiated on May 1, with over 200 public comments emphasizing the complexity and global nature of aerospace manufacturing. Among other comments, the Aerospace Industries Association (AIA) and Business Roundtable both highlighted that aerospace relies on deep cross-border integration, particularly with allied nations. They argued that trade restrictions would damage both commercial competitiveness and national security by undermining transatlantic partnership, thus voicing broader opposition to potential tariff actions and advocating against a determination that the existing state of imports threatens to impair national security.

Legal Authority and Proposed Reforms

Section 232 has withstood legal scrutiny. Most recently, in 2020, the U.S. Court of Appeals and the Court of International Trade considered legal challenges to President Trump’s tariffs on steel, ultimately affirming the constitutionality of these authorities and actions under Section 232. Currently, Congress’s role in Section 232 investigations remains limited, mostly requesting investigations and providing external consultations during the process. However, this role could be modified through proposed reform, such as those seeking Congressional authorization for tariff actions specific to Section 232 or under any authority before their employment, or limiting the scope of investigations through clearer definitions of national security. 

Conclusion

Section 232 has become an increasingly used tool, both for its broad authority to impose import restrictions on grounds of national security and its resilience to legal challenges. The Section 232 investigations initiated under the current Administration across industries show a consistent pattern: while stakeholders broadly share the need to safeguard national security through supply chain resilience for their industries, they caution against using blunt tools such as across-the-board tariffs and other measures that would meaningfully impact the current state of imports. Most public commenters favor a strategic mixture of investment incentives, international partnerships, targeted enforcement, and more direct support for domestic manufacturing rather than protection. The diversity and depth of the public input reveal not only sector-specific concerns but a collective recognition that US national security depends on both domestic capacity and allied collaboration. Should the Administration decide to impose tariffs after these investigations, as seems likely, it would mark a major strategic pivot towards economic security through protection of domestic industries.