U.S. Supreme Court [Photo = Yonhap News]

The U.S. Supreme Court ruled on the 20th (local time) that the global tariff measures pursued by U.S. President Donald Trump under the International Emergency Economic Powers Act (IEEPA) were unlawful.

The Court clarified that the constitutional authority over tariffs and taxation rests with Congress, thereby limiting the scope of interpretation for emergency economic powers.

In its ruling released today, the Supreme Court stated in a 6-3 majority opinion that "the IEEPA is a statute intended for financial sanctions and cannot be viewed as a delegation of authority to impose comprehensive tariffs."

Referencing Article I of the Constitution, the Court held that the executive branch's introduction of a new tariff system based on emergency powers infringed upon the legislative domain.

The majority opinion specifically applied the "major questions doctrine," which posits that tariff policies with broad economic impacts require clear congressional authorization.

The ruling emphasized the "clear statement rule," noting that when Congress delegates tariff authority, there must be a clear basis in the statutory language; the court pointed out that the IEEPA contains no language that directly authorizes the setting of tariffs.

The Court also cited existing legislative structures through which Congress has traditionally granted tariff authority as a point of comparison.

It highlighted that, unlike cases where tariff authority is explicitly provided—such as Section 232 of the Trade Expansion Act or Section 301 of the Trade Act—the IEEPA lacks the same level of delegatory language.

This is interpreted not as a judgment on the legality of those specific provisions, but as an additional explanation provided in the process of interpreting the scope of emergency economic powers.

The ruling also noted that tariffs effectively function as taxes.

The Court pointed out that if the executive branch expands into the realm of revenue-raising authority under the pretext of diplomatic or security situations, the constitutional principle of separation of powers could be undermined, stating that "the existence of an economic emergency does not suspend the constitutional structure of the separation of powers."

In contrast, the dissenting justices expressed the view that the President's discretion to respond should be recognized more broadly in abnormal situations, such as shocks to global supply chains.

However, the majority opinion drew a firm line, asserting that emergency economic powers cannot be allowed to transition into a general tool for trade policy.

Legal experts in the U.S. are assessing this ruling as a decision that goes beyond determining the legality of a specific tariff policy, effectively reaffirming the limits on the delegation of authority to the executive branch.

As the Supreme Court applies a strict textual interpretation to emergency economic powers, it is expected that judicial review standards for future executive orders in the economic and trade sectors will be significantly strengthened.