In 1952, President Harry Truman asserted his power as commander in chief to seize America’s major steel mills. He insisted that the emergency action was necessary to avert a strike that he believed would threaten national defense during the Korean War. By a 6–3 vote in the landmark case Youngstown Steel & Tube Co. v. Sawyer (1953), the Supreme Court disagreed. The majority opinion, written by Justice Hugo Black, held that Congress had refused to pass a statute that authorized the president to seize this kind of private property and, therefore, the president lacked legal authority for his actions. In the eyes of history, however, the more influential opinion was a concurrence by Justice Robert Jackson. In it, he emphasized the importance of defending liberty through the separation of powers.Last week, also by a 6–3 vote, the Supreme Court held that President Trump lacks the authority to impose tariffs under the International Emergency Economic Powers Act. The majority opinion, written by Chief Justice John Roberts, held that the text of the statute authorizes the president to “regulate” imports but that the word regulate does not include the power to tax. The concurring opinion of Justice Neil Gorsuch emphasized the importance of defending the separation of powers to check the consolidation of executive power. Following in Jackson’s footsteps, Gorsuch’s concurring opinion may become the Roberts Court’s most influential statement on how to prevent the steady accretion of executive power by encouraging Congress to do its job. (Gorsuch is a co-chair of the National Constitution Center, where I serve as CEO emeritus.)Gorsuch did join Roberts’s majority opinion in full, but it was in his concurrence where he sought to defend his vision of the major-questions doctrine, which he defined as the idea that “the President must identify clear statutory authority for the extraordinary delegated power he claims.” Citing cases “across many fields,” he observed that officials claiming “substantial” powers have traditionally been required to ground their claims in a “clear legislative basis” or “definite and unmistakable expression.” Since “highly resourceful members of the executive branch have strong incentives to exploit any doubt in Congress’s past work to assume new power for themselves,” the major-question doctrine’s requirement that Congress must speak clearly when delegating power to the executive branch “helps prevent that kind of exploitation.” Gorsuch depicts the major-questions doctrine as a fulfillment of the Founders’ vision by preventing “the few (or the one)” from expanding “their power based on loose or uncertain authority.”Gorsuch goes on to criticize nearly all his colleagues’ approaches to interpreting statutes. First, Gorsuch responds to the criticisms of Justices Elena Kagan, Sonia Sotomayor, and Ketanji Brown Jackson, who “insist,” he writes, that “they can reach the same result by employing only routine tools of statutory interpretation.” Gorsuch argues that their narrow constructions of statutory text in a case denying Trump’s authority is at odds with their broad constructions of statutory text in other cases that would have expanded Joe Biden’s. In particular, Gorsuch says that Sotomayor and Kagan managed to somehow find “expansive language” in statutes in order to justify Biden policies such as a vaccine mandate for workers of large companies, COVID regulations on landlords and tenants, and the cancellation of $430 million in student-loan debt.In the past, the liberal justices have criticized the major-questions doctrine as “a novelty without basis in law” and “an anti-administrative-state stance.” Gorsuch responded that the major-questions doctrine is not “anti–administrative state” but instead “pro-Congress.” In his view, it protects congressional prerogatives from resourceful presidents, who are likely to exploit ambiguities in statutes to seize power for themselves. (Gorsuch’s argument is most convincing when the president, rather than administrative agencies, are exploiting the ambiguities.)[David Frum: The Supreme Court delivers Trump a humiliating gift]Moreover, he worries that without something like the major-questions doctrine, the power of the president will expand infinitely at the expense of the other branches: “Once this Court reads a doubtful statute as granting the executive branch a given power, that power may prove almost impossible for Congress to retrieve.” This argument closely tracks his observation during oral argument that, without a veto-proof supermajority, “Congress, as a practical matter, can’t get this power back once it’s handed it over to the President. It’s a one-way ratchet toward the gradual but continual accretion of power in the executive branch and away from the people’s elected Representative.”After addressing the critics of the major-questions doctrine, Justice Gorsuch then addresses its supporters. He first turns to Justice Amy Coney Barrett, who also joined the principal opinion in full. “I understand Justice Gorsuch to require Congress always to speak precisely to any major power that it intends to give away,” Barrett writes. “But if the Constitution permits Congress to give the Executive a particular power, who are we to get in the way?” Gorsuch takes issue with Barrett’s attempts to recast the major-questions doctrine as a common sense way of interpreting texts in order to “soften its blow.” Instead of an ordinary principle of statutory interpretation, he believes that the doctrine should be conceptualized as “a ‘dice-loading’ rule” that requires a clear legislative statement for any executive claims of “extraordinary delegated power.”Gorsuch then addresses his dissenting conservative colleagues. Justice Brett Kavanaugh argues that “strict limitations upon congressional delegation of power to the president over internal affairs do not apply with respect to delegation of power over external affairs.” In response, Gorsuch contends that this broad exception to the major-questions doctrine would allow Congress to delegate “not only the power to impose tariffs, but also the power to establish uniform rules of naturalization, appropriate money for armies,” and other core powers that the Framers expected Congress to exercise.Gorsuch then turns to the “final camp” and criticizes Justice Clarence Thomas for being an inconsistent originalist. In an idiosyncratic opinion, Thomas argues that the nondelegation doctrine forbids Congress only from “delegating core legislative power, which is the power to make substantive rules setting the conditions for deprivations of life, liberty, or property.” Thus, to Thomas, the “power to impose duties on imports can be delegated,” since “foreign commerce was not within the core legislative power, and engaging in foreign commerce was regarded as a privilege rather than a right.” Gorsuch rebukes Thomas’s version of constitutional history and argues that his position is also inconsistent with the text of the Constitution, early congressional practice, and Supreme Court precedent. In a notable passage, Gorsuch points out that “it was duties on foreign tea that triggered the Boston Tea Party.” Gorsuch asks, “Are we really to believe that the patriots that night in Boston Harbor considered the whole of the tariff power some kingly prerogative?”In the 1953 steel-seizure case, Jackson concluded with a warning about the importance of parliamentary deliberation to check a tyrannical executive. “For all its defects, delays, and inconveniences, men have discovered no technique for long preserving free government except that the Executive be under the law and that the law be made by parliamentary deliberations,” he wrote.[Ilya Somin: How the Supreme Court spared America]Gorsuch ends on a similar note. Like Jackson, he issued a solo concurrence that struck down a unilateral presidential action with major foreign-policy implications by a president of his own party. Like Jackson, Gorsuch did not allow presidential claims of emergency power to justify extraordinary intrusions into core congressional authority. Like Jackson, Gorsuch developed a jurisprudential framework with an eye toward future cases about the separation of powers. And like Jackson, Gorsuch concluded his opinion with a paean to the value of legislative deliberation:“The deliberative nature of the legislative process was the whole point of its design,” Gorsuch wrote. “Through that process, the Nation can tap the combined wisdom of the people’s elected representatives, not just that of one faction or man.” He continued, “If history is any guide, the tables will turn and the day will come when those disappointed by today’s result will appreciate the legislative process for the bulwark of liberty it is.”It is a warning about the importance of the separation of powers that all Americans should heed.