The Supreme Court’s decision invalidating the Trump administration’s tariffs under the International Emergency Economic Powers Act was neither revolutionary nor catastrophic. It was, instead, doctrinal housekeeping. The Court held, cleanly and without melodrama, “that IEEPA does not authorize the President to impose tariffs.”
That’s the whole ballgame. Not that tariffs are unconstitutional. Not that the president lacks authority to levy them in all circumstances. Only that this law—the one on which the solicitor general relied—doesn’t confer the power claimed.
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The majority’s reasoning rests on a premise that should surprise no first-year law student: tariffs are taxes. As Chief Justice John Roberts explained, “The power to impose tariffs is ‘very clear[ly] . . . a branch of the taxing power.’” Article I vests that power in Congress. And, Roberts continued, “They did not vest any part of the taxing power in the Executive Branch.”
IEEPA authorizes the president to “investigate, block during the pendency of an investigation, regulate, direct and compel, nullify, void, prevent or prohibit” various economic transactions. What it does not mention is tariffs. As the Court noted, “Absent from this lengthy list of powers is any reference to tariffs or duties.” Congress knows how to authorize duties when it wants to.
The administration’s fallback argument was that the statutory power to “regulate . . . importation” naturally includes the power to impose tariffs. But Roberts dismantled that claim with surgical precision: “The Government cannot identify any statute in which the power to regulate includes the power to tax.” As the Court reminded us, tariffs “operate directly on domestic importers to raise revenue for the Treasury” and are “a branch of the taxing power.”
And here’s the kicker: “None of IEEPA’s authorities includes the distinct and extraordinary power to raise revenue.”
One can almost hear the ghost of NFIB v. Sebelius rustling in the background. In 2012, Roberts infamously saved Obamacare by transmogrifying the individual mandate into a tax. The Constitution’s taxing power, he explained then, was capacious enough to sustain a rule that someone be required to buy taxed for not buying health insurance.
Today, Roberts also labels tariffs taxes, but this time, that label is fatal. Because if tariffs are taxes, then Congress must clearly delegate the authority to levy them. It didn’t. Roberts giveth and Roberts taketh away.
To be fair, the decision is narrow—intentionally so. Justice Brett Kavanaugh, joined by Justices Clarence Thomas and Samuel Alito, noted in dissent that “numerous other federal statutes authorize the President to impose tariffs and might justify most (if not all) of the tariffs at issue in this case.” That observation is indisputable—and an invitation.
Congress has enacted targeted trade statutes for decades, many of them requiring specific findings, investigations, or time limits. Treasury Secretary Scott Bessent, less enamored of tariffs as an instrument of economic policy than his boss, has been discussing those alternatives for months in anticipation of this ruling.
The ruling’s practical effect may well be salutary. A uniform global tariff justified by a free-floating emergency was always economically clumsy and strategically incoherent. Targeted, statute-grounded tariffs, whether under Section 232 or other authorities, are more defensible legally and more disciplined as policy. The Court hasn’t thrown out the trade playbook. It’s just told the administration to run the right play.
The more interesting doctrinal skirmish concerned the “major questions doctrine.” Roberts, joined only by Justices Neil Gorsuch and Amy Coney Barrett, emphasized that when a president asserts sweeping power, he must “point to clear congressional authorization.” Roberts rejected the government’s argument that “the doctrine should not apply to emergency statutes,” foreclosing the idea that invoking an “emergency” is a constitutional cheat code.
Justice Gorsuch, in a characteristically muscular concurrence, framed the issue as structural: “The Constitution lodges the Nation’s lawmaking powers in Congress alone, and the major questions doctrine safeguards that assignment against executive encroachment.” One need not embrace every iteration of the doctrine to appreciate the point. If you’re reorienting global trade flows, Congress should unmistakably have authorized you to do so.
The liberal justices were content to join the statutory holding while sidestepping the “major questions” analysis. That preserves flexibility for future cases. Just as they were comfortable upholding President Biden’s constitutionally unmoored vaccine mandate, one can imagine them approaching a different emergency—perhaps climate-related—quite differently under a President AOC. The restraint here is politically convenient.
Justice Thomas’s dissent is the real surprise. In recent years, Thomas (alongside Gorsuch) has been the Court’s most forceful skeptic of sweeping congressional delegations. Yet here he read IEEPA expansively. That departure from his usual separation-of-powers instincts is puzzling. Thomas argues that Congress may not delegate “rules setting the conditions for deprivations of life, liberty, or property”—but don’t tariffs deprive people of property? The line he draws is hard to square with the Constitution’s text or structure.
Justice Kavanaugh’s dissent, by contrast, is less startling. His experience in the executive branch has long made him attentive to presidential flexibility in foreign affairs. But as Roberts pointed out, there’s no “foreign affairs exception” to the basic requirement that Congress speak clearly when handing over core Article I powers.
And then there’s Justice Ketanji Brown Jackson, who wrote a separate concurrence resting on legislative history—an opinion that, tellingly, no other justice joined. In a case where statutory text was front and center, turning to congressional committee reports feels like looking for circumstantial evidence after the statute has already confessed.
In the end, the decision is less a rebuke than a reminder: Congress controls the taxing power. If it wishes to arm the president with sweeping tariff authority, it must do so unmistakably. Until then, presidents must work with the tools Congress has actually provided.
Photo by Kyle Mazza/Anadolu via Getty Images