When the Supreme Court first articulated the major questions doctrine a few years ago, many viewed it primarily as an antiregulatory tool. But as the Court has applied the doctrine, it is more aptly understood as “an interpretive tool” that draws heavily on “common sense as to the manner in which Congress is likely to delegate [certain] policy decision[s].” The doctrine thus applies to “extraordinary cases” challenging all manner of executive actions. Recent cases challenging President Trump’s use of the International Emergency Economic Powers Act (IEEPA) to impose tariffs prove the point. As I and other colleagues at the Institute for Policy Integrity explain in a brief supporting one challenge to those tariffs, the President’s use of IEEPA triggers the major questions doctrine because it is an unheralded and transformative use of the statute that also has vast economic and political significance.

We filed our amicus brief in this challenge to the Trump Administration for the same reason we filed amicus briefs in challenges to the Biden Administration’s actions that raised the major questions doctrine: We were concerned that litigants were presenting incomplete descriptions of the doctrine, which could lead to its overbroad application in lower courts. In case after case, litigants argued that the major questions doctrine applied to all questions of economic and political significance. (The same has been true in the tariff cases, see here and here.) While “economic and political significance” may be a common shorthand for the doctrine, it is far too nebulous a test for a doctrine meant to apply in “extraordinary cases.” Rather, as we explain at length in our brief, the Supreme Court’s majority opinions applying the major questions doctrine have always analyzed the history, transformative breadth, and economic and political significance of the challenged action when determining whether the major questions doctrine applies. If it does, the action requires “clear congressional authorization.”

The Major Questions Doctrine Still Applies Only in “Extraordinary Cases”

Taking a step back, the Supreme Court first expressly applied the major questions test in 2022 in West Virginia v. EPA, which addressed the Obama-era Clean Power Plan, and applied it again in Biden v. Nebraska to invalidate President Biden’s student loan forgiveness program. These two cases (and others that immediately predate those decisions that have been understood as precursors) suggested to some that the doctrine was principally a deregulatory tool wielded against agency action in such areas as climate, education, and public health.

But the recently filed lawsuits arguing that President Trump’s tariffs—including his “Liberation Day” order imposing near-universal tariffs up to 50% and orders imposing even higher rates on China—trigger the major questions doctrine demonstrate that the doctrine is simply a tool of statutory interpretation. And while litigants often misapply the major questions test by placing undue emphasis on the economic or political significance prong, the Supreme Court has never found that economic and political significance alone is sufficient to trigger the doctrine. Instead, all three factors indicating the existence of an “extraordinary case” must be present: (1) history, (2) breadth, and (3) economic and political significance.

Placing dispositive weight on economic and political significance alone would apply the doctrine more broadly than under existing Supreme Court precedent. Each year, the government issues dozens of rules with an annual economic effect of over $100 million. The Supreme Court has only identified a handful of “extraordinary cases” across 30 years of decisions laying the foundation for the doctrine. Even in recent cases involving massive programs like Medicare, the Court has not invoked major questions. Litigants hoping to apply the doctrine must therefore tread lightly to avoid extending the doctrine too far.

The Major Questions Doctrine Applies to President Trump’s Tariffs

The President’s tariff orders rely on IEEPA, a statute that authorizes the President to take a range of actions to address “any unusual and extraordinary threat . . . to the national security, foreign policy, or economy of the United States.” The history, breadth, and economic and political significance of the asserted authority all indicate that the major questions doctrine properly applies.

History. The history prong addresses whether the government’s action is “unheralded,” or unlike any action taken before under the statute.

As our brief explains, President Trump’s tariffs represent the first time a president has used IEEPA to impose tariffs in the nearly half-century since Congress passed the statute. Past presidents—including President Trump during his first term—consistently used the statute to impose economic sanctions like import bans and asset freezes. In fact, when President Trump previously sought to impose tariffs, he relied on specific trade statutes instead of IEEPA. Thus, the use of IEEPA to impose tariffs is “unheralded.”

Breadth. The breadth prong of the analysis concerns whether the government’s assertion of authority demonstrates a “transformative expansion” of power.

In our brief, we point out how previous uses of IEEPA addressed specific threats or hostile actors. For example, presidents have imposed sanctions concerning chemical and biological weapons proliferation and have blocked the transfer of property to transnational criminal organizations, cyber-criminals, or those involved in foreign conflicts. The President’s use of IEEPA to address “large and persistent annual U.S. goods trade deficits” transforms a narrow tool for imposing targeted sanctions during national emergencies into a blank check to set national trade and fiscal policy.

Economic and Political Significance. The economic and political significance of the government’s action is relevant to the analysis, though not dispositive.

Our brief argues that the IEEPA tariffs qualify as economically and politically significant under any reasonable standard. The Tax Foundation projected that the tariffs will reduce U.S. gross domestic product by 0.8% even before any foreign retaliation, amounting to over $200 billion per year or more than $2 trillion over ten years. That economic effect more than qualifies as “significant” compared to the effects deemed significant in other major questions cases, including the estimated $50 billion single-year cost of President Biden’s eviction moratorium and the over $450 billion ten-year cost of his student debt-relief program. And there are few decisions more politically fraught, or subject to “earnest and profound debate,” than taxation.

Because all factors indicating the existence of an extraordinary case are present, the major questions doctrine applies and the government must identify “clear congressional authorization” under IEEPA for the President’s asserted power.

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The outcome of the tariff suits will help determine the reach of the major questions doctrine in constraining executive action under the Trump Administration and future administrations. Our brief demonstrates how litigants can apply the doctrine effectively while limiting its reach to truly extraordinary cases.

Kelly McGee is a Legal Fellow at the Institute for Policy Integrity at NYU School of Law. This post does not purport to represent the views, if any, of NYU School of Law.