The U.S. Supreme Court on Friday invalidated President Donald Trump’s use of the International Emergency Economic Powers Act to impose sweeping tariffs, marking a rare limit on presidential trade authority. In a decision authored by Chief Justice John Roberts, the court ruled that IEEPA does not grant the executive branch unchecked power to disrupt global commerce without congressional approval. The move halts tariffs on imports from China, Mexico, Canada and the European Union, which Trump enacted early in his second term after declaring a national economic emergency.

Legal experts hailed the outcome as a landmark affirmation of separation of powers. Richard H. Fildes, a New York University School of Law professor, called it “the most significant case since the Supreme Court rejected President Harry S. Truman’s seizure of steel mills during the Korean War.” Fildes told reporters the decision highlights constitutional boundaries on emergency powers. The court’s conservative majority joined with the three liberal justices, bucking expectations after prior support for Trump on immigration and other issues.

Trump lashed out immediately on Truth Social, labeling the justices “fools and flatterers” and the ruling “absurd.” Hours later, his administration announced withdrawal of some emergency-based tariffs while imposing fresh 10% duties on global imports through alternative statutory channels. White House officials said they aim to comply with the decision while protecting American workers.

U.S. media dissected the political fallout. The Washington Post framed it as a “painful political setback for Trump” and a historic curb on presidential authority. The New York Times described the verdict as proof of the court’s independence, noting its nonpartisan stance amid criticism of past rulings. The Wall Street Journal praised the decision for shielding future presidents from similar overreach, dubbing it a “day of tariff liberation.” Without this check, the Journal noted, any president could sidestep Congress on trade using emergency pretexts.

Global outlets weighed in swiftly. The BBC declared an end to the era when a president could unleash triple-digit tariffs with a single stroke. The Guardian saw it as evidence that America’s rule-of-law system endures. Yet analysts warned of turbulence ahead. Countries from South Korea to Germany, already reeling from Trump’s initial tariff salvos since January 2025, now brace for policy whiplash as Washington hunts workarounds.

Reuters quoted trade experts predicting no quick relief for world markets. Lingering uncertainty over prices, supply chains and retaliation could drag on, they said. The ruling arrived amid Trump’s aggressive second-term push to revive manufacturing, with tariffs targeting $500 billion in annual imports. Importers face refunds on duties already collected, but new levies loom under Section 232 national security provisions or Section 301 unfair trade practices.

The decision stems from lawsuits filed by U.S. businesses and states battered by higher costs. Plaintiffs argued IEEPA, enacted in 1977 to address genuine crises like the Iranian hostage standoff, never authorized open-ended trade wars. Lower courts split before the Supreme Court took up the case last fall. Oral arguments in December revealed deep divisions, with Justice Brett Kavanaugh questioning the law’s scope.

Economists project the block could lower U.S. consumer prices by 1-2% over the next year, according to a Peterson Institute analysis. Steel and aluminum tariffs from Trump’s first term, upheld separately, remain intact. Trump vowed to seek legislative fixes from a Republican-led Congress, signaling a potential shift to bipartisan trade deals.

For the international community, the verdict tempers fears of unchecked U.S. unilateralism but introduces fresh variables. South Korean officials, citing impacts on their auto exports, welcomed the ruling while preparing for Trump’s next moves. European Commission President Ursula von der Leyen called for urgent WTO consultations to counter any evasion tactics.