My previous articles on the president’s powers have centred on issues such as vetoing and military command. In recent months, however, my students have asked me about what legal authority the president has in relation to levying tariffs. One of President Trump’s favourite words is supposedly “tariff” and we have of course seen him impose tariffs, or threaten to impose tariffs in some cases. For Trump, this is all part of his “art of the deal” strategy in which high demands and the projection of strength are used to leverage more favourable concessions.
But Trump’s use of tariffs has invited growing media and legal scrutiny over their legitimacy within the framework of the Constitution and the potential economic effects of them. This article examines the historical foundations of the president’s ability to impose tariffs, the legal and economic debates that surround their use, and the recent judicial response to Trump’s expansive tariff agenda.
The Legal Foundation of Presidential Tariff Powers
Article I, Section 8 of the US Constitution vests Congress with the power to “lay and collect Taxes, Duties, Imposts and Excises”. In principle, then, the authority to impose tariffs lies squarely with the legislative branch. However, Article II, Sections 2 and 3, indicate the president is the USA’s chief diplomat so this gives him the authority to negotiate with other countries, so it could be inferred the president has a role in setting tariffs. Over time, Congress has delegated increasing discretion to the president through a series of legislative measures designed to give the executive branch flexibility in responding to global trade challenges.
Key statutes include:
- The Trade Expansion Act of 1962 (Section 232), which allows the president to impose tariffs on imports that threaten national security, following an investigation by the Department of Commerce.
- The Trade Act of 1974, which includes Section 201, enabling the president to implement temporary relief measures for domestic industries suffering from import surges, and Section 301, which authorises retaliation against unfair trade practices by foreign governments.
- The International Emergency Economic Powers Act (IEEPA) of 1977, which allows the president to regulate commerce in response to a national emergency that presents an “unusual and extraordinary threat” to the United States, particularly in matters involving foreign entities.
While these statutes have expanded the president’s capacity to act unilaterally in trade matters, they are not without limits. The use of these powers is subject to judicial review and, increasingly, political scrutiny, especially when tariffs have far-reaching economic or diplomatic consequences.
Historic Legal and Economic Responses to Executive Tariffs
Legally, most tariffs imposed under Section 232 or Section 301 have been upheld by U.S. courts, even as they have prompted complaints and challenges at the World Trade Organisation (WTO). However, the broader use of IEEPA to impose tariffs, particularly as a tool for general economic protectionism, has provoked more serious legal doubts. Critics argue that this stretches the statute beyond its original purpose, which was designed to address national emergencies, not global trade rebalancing.
Economically, presidential tariffs have produced mixed results. Proponents argue they provide necessary protection for vulnerable domestic industries and give the president leverage in international negotiations. Indeed, in the short term, sectors such as steel and aluminium have benefitted from reduced foreign competition.
Yet the downsides have also been significant:
- Retaliatory tariffs by foreign governments have impacted American exporters, particularly in agriculture and manufacturing.
- Consumer prices have increased due to higher costs for imported goods and disrupted supply chains.
- Global uncertainty around U.S. trade policy has undermined investor confidence and the rules-based international trading system.
Analyses by economists and trade experts suggest that while targeted tariffs can offer short-term benefits, their broader application often leads to inefficiency, inflationary pressures, and geopolitical tension.
Strategic and Political Benefits of Trump’s Tariffs
While the legal and economic downsides of Trump’s tariff strategy have attracted significant criticism, it is important to acknowledge the perceived benefits that underpinned their implementation—both from a policy and political standpoint.
1. Leverage in Trade Negotiations
A key strategic rationale for Trump’s tariffs was their use as bargaining tools in international negotiations. By imposing or threatening tariffs, the administration sought to extract more favourable terms from major trading partners. In 2019, this tactic contributed to the signing of the Phase One trade agreement with China, which included commitments on intellectual property rights, currency practices, and increased agricultural purchases. Similarly, Trump’s use of tariff threats with Mexico and Canada helped secure revisions to NAFTA, culminating in the United States–Mexico–Canada Agreement (USMCA).
2. Protection of Domestic Industries
The administration’s Section 232 tariffs on steel and aluminium, as well as Section 201 tariffs on solar panels and washing machines, were framed as necessary to protect domestic manufacturing from unfair foreign competition—particularly from China. In the short term, these measures led to increased investment and output in some affected industries. Steel production and pricing rebounded temporarily, and some manufacturers reported renewed hiring.
3. Reassertion of Tariff Policy as Economic Statecraft
Trump’s presidency marked a notable shift from decades of bipartisan support for multilateral trade liberalisation. Tariffs—long considered a relic of pre-WTO policy—were reintroduced as tools of economic nationalism and statecraft. For supporters, this represented a necessary correction to globalisation’s perceived harms to American workers and industry.
4. Targeted Trade Deficit Reduction
Although the overall U.S. trade deficit grew during Trump’s term (partly due to macroeconomic factors and the COVID-19 pandemic), the bilateral trade deficit with China did decline in 2019—falling by over 17% compared to the previous year. Supporters viewed this as evidence that tariffs could pressure countries to change trade practices and reduce imbalances.
5. Political Resonance with Key Voter Blocs
Trump’s tariff policy was also popular with blue-collar voters in industrial regions. Tariffs were framed as a defence of American jobs and national pride, aligning with a broader populist message that resonated in states such as Michigan, Pennsylvania, Ohio, and Wisconsin—all crucial to Trump’s 2016 electoral success.
While the long-term sustainability of these benefits remains debated, they form a central part of the justification offered by Trump and his allies. Any comprehensive analysis of presidential tariff power must therefore consider not only the legal constraints and economic risks, but also the strategic and political logic underpinning their use.
The Trump Administration and the Boundaries of Tariff Power
Donald Trump’s approach to tariffs, especially in recent months, marked a significant expansion of presidential power in this area. In addition to using Sections 232 and 301, Trump introduced sweeping tariffs on a broad range of imports under the IEEPA, declaring a national emergency linked to trade imbalances, industrial decline, and border security.
Dubbed the “Liberation Day” tariffs by his administration, these measures sparked intense legal scrutiny. While previous presidents had used IEEPA primarily to target specific countries or foreign threats, such as terrorism or nuclear proliferation, Trump used it to apply global tariffs in the name of economic recovery and national competitiveness.
This use of IEEPA may be novel, but novelty alone does not make an executive action illegal. The U.S. legal system often entertains unprecedented uses of presidential power, and courts evaluate such actions based on their adherence to statutory language and constitutional principles.
While no prior president had used IEEPA to impose general economic tariffs, that fact alone did not automatically render Trump’s actions unlawful. Courts do not strike down executive measures solely because they are unprecedented. Instead, they examine whether the president’s actions fall within the scope of delegated legislative authority, and whether they satisfy procedural and constitutional standards.
Supporters of Trump’s tariffs pointed to the broad language of IEEPA and the president’s discretion to define what constitutes a national emergency. Critics countered that the economic issues cited, such as the trade deficit and industrial decline, did not meet the threshold of an “unusual and extraordinary threat” required by the statute. They further argued that allowing the president to unilaterally impose tariffs under such vague justifications effectively undermines Congress’s exclusive power over taxation and trade.
In V.O.S. Selections, Inc. v. U.S. (2025), the U.S. Court of International Trade ruled that Trump’s use of IEEPA in this context exceeded the limits of the law. The court found that the declared emergency lacked both urgency and a genuine foreign threat, and that the tariffs amounted to an improper use of executive power for economic policymaking. The decision emphasised that the IEEPA was never intended to function as a backdoor mechanism for tariff reform.
However, the matter is far from settled. In June 2025, a federal appeals court issued a stay on the lower court’s ruling, allowing the tariffs to remain in place pending full review. Oral arguments are scheduled for July, and the final decision will likely have lasting implications for the balance of power in U.S. trade policy.
The Broader Constitutional and Political Debate
The Trump-era tariffs have reignited a long-standing constitutional debate: how far should Congress delegate economic powers to the executive branch? While flexibility in responding to trade challenges is important, critics argue that excessive delegation weakens democratic accountability and undermines the principle of checks and balances.
The legal controversy surrounding IEEPA has also raised questions about the nondelegation doctrine, the idea that Congress must provide an “intelligible principle” when handing powers to the executive. If the courts rule that IEEPA gives the president too much latitude to define emergencies and impose tariffs without oversight, it could trigger a legislative or judicial push to narrow the statute’s scope.
Legislative proposals such as the Trade Review Act of 2025, which would require presidential tariffs to be approved by Congress within 60 days, aim to restore that balance. Whether such efforts gain traction remains to be seen, but the judicial review of Trump’s use of IEEPA suggests that constitutional safeguards remain active in curbing executive overreach.
Conclusion
The power to impose tariffs has become a potent tool of presidential policymaking. While rooted in congressional delegation, its use (especially through emergency powers) raises complex legal and constitutional questions. The Trump administration’s tariffs under Section 232 and Section 301 fell within established legal precedent, though they provoked economic and diplomatic controversy. By contrast, the use of the IEEPA to impose broad, global tariffs represented a legally novel, and judicially contested, expansion of executive power.
Ultimately, the question is not whether novel uses of presidential authority are permitted, but whether they are justified by law and anchored in constitutional norms. The outcome of the IEEPA litigation will not only determine the fate of Trump’s tariffs but may also reshape the contours of presidential power in economic affairs for years to come.
