Multiple authoritative and highly relevant sources, including the official U.S. Supreme Court opinion and major credible news outlets, consistently report that the Supreme Court issued a 6–3 decision ruling tariffs imposed during Donald Trump's presidency as illegal. The official opinion directly confirms the case and decision while detailing the legal reasoning. Trusted media coverage from NPR, NBC News, the Los Angeles Times, and The Guardian aligns on key facts: the decision date (February 20, 2026), the 6–3 vote, and the finding that Trump's tariffs violated legal constraints, particularly due to overstepping executive power. The language across these reports is consistent with the statement's claim, and no credible primary source contradicts the assertion. While some coverage notes that not all tariffs were struck down, the core claim that the Court ruled them illegal in a significant decision is amply supported. Hence, the probability of truth is high, with a small reservation due to nuanced differences in scope ('most tariffs' vs. all tariffs). This nuance slightly reduces the probability from absolute certainty but does not change the overall assessment.