The Supreme Court ruled 6-3 that President Trump exceeded his authority under the International Emergency Economic Powers Act when he imposed sweeping tariffs on imports from Canada, Mexico, China, and dozens of other countries. Justice Brett Kavanaugh fired back with a 63-page dissent that left no ambiguity about where he stands.

The case originated with challenges brought by several Democrat-led states and small businesses, who argued the administration's actions violated the "major questions doctrine," which requires clear congressional authorization for sweeping executive actions.

The majority agreed, rejecting the administration's argument that tariffs fall within the president's foreign affairs authority. Trump reportedly called the decision "a disgrace" during a White House meeting with governors.

The core of Kavanaugh's argument

Kavanaugh's dissent was not a mere protest vote. At 63 pages, it was a systematic dismantling of the majority's reasoning, built on statutory text, legislative history, and presidential precedent stretching back decades, Newsmax reports.

His central argument is straightforward: IEEPA, enacted in 1977, grants the president authority to "regulate … importation." If that language permits embargoes and quotas, both of which block or limit goods from entering the country entirely, then it logically permits tariffs, which merely impose a cost on those goods. An embargo is a sledgehammer. A tariff is a tap on the shoulder. The Court ruled the sledgehammer is fine but the tap is not.

"This case does not involve elephants in mouseholes. This case instead involves an elephant (tariffs) in a statutory elephant hole."

That line is aimed squarely at the major questions doctrine, which the majority invoked to argue that Congress never clearly authorized the president to impose tariffs of this magnitude. Kavanaugh's counter: Congress didn't hide this authority in some obscure subclause. It wrote "regulate … importation" in a statute explicitly designed to give the president broad emergency economic powers. The authority is exactly where you'd expect it to be.

He also pointed to historical precedent. Presidents Nixon and Ford used similar statutory language to justify tariffs before IEEPA was enacted. When Congress passed IEEPA in 1977, it reenacted the phrase "regulate … importation" with that history in full view. If Congress disagreed with how previous presidents interpreted that language, it had every opportunity to narrow the text. It chose not to.

What the majority got wrong

Roberts wrote that the Framers "did not vest any part of the taxing power in the Executive Branch." That's a serious constitutional point, and it's not wrong as a matter of original design. But Kavanaugh's dissent doesn't rest on inherent executive power. It rests on congressional delegation. Congress passed IEEPA. Congress chose the language. The question is what that language means, not whether presidents should have taxing power in the abstract.

This is the tension the majority never fully resolved. IEEPA unquestionably allows the president to:

• Block imports entirely (embargoes)
• Limit the quantity of imports (quotas)
• Freeze foreign assets
• Restrict financial transactions

Every one of those tools is more economically disruptive than a tariff. The majority's position requires you to believe that Congress gave the president a toolbox containing a chainsaw, a sledgehammer, and a wrecking ball, but drew the line at a wrench.

Kavanaugh stressed that the policy wisdom of tariffs is a separate question entirely, one for voters and lawmakers, not judges. The Court's job is to read the statute. And the statute, as written, is broad.

The fight moves, it doesn't end

Administration officials have signaled they are prepared to pursue tariffs under other trade laws. The Trade Act of 1974 provides alternative statutory authority for presidential action on trade, and the administration's legal team clearly anticipated this ruling as a possibility worth planning around.

The tariffs at issue were substantial. Trump had imposed a 25% duty on many Canadian and Mexican imports, a 10% duty on Chinese goods that eventually climbed as high as 145%, and a 10% baseline tariff on imports from most trading partners with higher rates for dozens of countries. These were tied to declared national emergencies involving drug trafficking and trade imbalances.

None of that goes away because of this ruling. The underlying emergencies remain. The trade imbalances remain. The fentanyl crisis remains. What changes is the legal vehicle, not the destination.

A Court divided on power, not principle

The 6-3 split is notable. This was not the familiar left-right divide. Roberts sided with the majority, which means at least two justices typically sympathetic to executive authority drew a line here. The question of where presidential power ends and congressional authority begins is one that reshuffles alliances depending on who holds the White House, a pattern worth watching as trade policy continues to evolve.

But Kavanaugh's dissent will outlast the headlines. Sixty-three pages of textual analysis, historical documentation, and logical reasoning don't vanish because the majority went the other way. Dissents have a way of becoming majority opinions in future cases. Ask anyone who read Justice Scalia's for a few decades.

For now, the statute says what six justices say it says. Kavanaugh made the case that they read it wrong. History will decide who was right.