The Supreme Court of the United States has dealt a significant legal and political setback to Donald Trump’s economic agenda by ruling that most of his broad global tariffs are unlawful. The decision was issued today in a 6–3 majority opinion written by John Roberts, marking one of the most consequential U.S. trade and constitutional rulings of this Supreme Court term.

Background — What the Case Was About

Beginning in 2025, President Trump used the International Emergency Economic Powers Act (IEEPA) — a 1977 law that lets a president regulate economic transactions during a national emergency — to impose a sweeping set of tariffs on imports from dozens of countries, including key U.S. trade partners such as Canada, China, Mexico, and others. These levies were pitched by the administration as tools to address trade imbalances, unfair practices, and other issues. However, challengers argued that tariffs are essentially taxes, and only Congress has the constitutional authority to levy taxes or duties on international trade.

The case — consolidated under Learning Resources, Inc. v. Trump and V.O.S. Selections, Inc. v. Trump — reached the Supreme Court after lower federal courts ruled Trump exceeded his legal authority.

What the Supreme Court Held

In today’s 6–3 ruling, the Court held:

• The IEEPA does not authorize a president to impose broad tariffs on imported goods. Such power is a taxing authority reserved for Congress under the U.S. Constitution.
  
  

• Chief Justice Roberts emphasized that “Congress did not vest any part of the taxing power in the Executive Branch,” rejecting the administration’s interpretation that emergency powers included tariff authority.
  
  

• Several justices in the majority — including some conservative appointees — agreed that if Congress had truly intended to grant such broad tariff powers to the president, it would have done so explicitly, as it has in other trade statutes.
  
  

The three dissenting justices — Clarence Thomas, Samuel Alito, and Brett Kavanaugh — argued that the law could be read to allow the administration’s actions, and that the Court was overstepping by second-guessing the policy choices of the executive branch.

Political and Economic Impact

Blow to Trump’s Trade Policy

The ruling is a dramatic rebuke of one of Trump’s most ambitious second-term economic strategies — and a rare instance of the Supreme Court checking presidential power after a string of other decisions that allowed executive actions to proceed.

Financial Implications

The IEEPA-based tariffs collected billions in revenue while in place. With the Supreme Court’s decision, businesses and importers that paid those duties may pursue refunds, potentially involving hundreds of billions of dollars in claims.

Global Trade and Markets

International markets and U.S. trade partners will likely reassess trade strategies and ongoing negotiations. Economists say the ruling could ease some tensions that had built under Trump’s tariff measures, though effects on prices, supply chains, and consumer goods may take time to unfold.

Executive Power Limits

Beyond tariffs, the ruling underscores broader constitutional limits on presidential authority, particularly when it comes to separation of powers between Congress and the executive branch — a theme central to ongoing U.S. legal debates.

Looking Ahead

While today’s ruling halts the bulk of the IEEPA-based tariffs, the Trump administration says it may pursue alternative legal bases for import levies using other statutory authorities. Additionally, the broader implications of this decision could influence future disputes over executive actions in trade, national security, and economic policy.

If you’d like, I can also provide a timeline of the legal battle over the tariffs from the original federal court challenge through the Supreme Court decision.

Sources: Forbes, CBS News, Al Jazeera, Reuters