A legal argument that the US Supreme Court used to foil Joe Biden on climate change and student debt now looms as a threat to President Donald Trump’s sweeping tariffs.During Biden’s presidency, the court’s conservative majority ruled that federal agencies can’t decide sweeping political and economic matters without clear congressional authorization.

The rulings against the levies in two federal courts – the U.S. Court of International Trade and the U.S. District Court in Washington, D.C. -- centered on Trump's unprecedented invocation of the International Economic Emergency Powers Act as a legal justification for tariffs.