One big question is whether the justices’ own expansive view of presidential authority allows for President Trump’s tariffs without the explicit approval of Congress.

U.S. President Donald Trump’s key tool for deploying tariffs will face a critical legal test in the Supreme Court on Wednesday — one which could upend his plans to realign global trade.

Trump has heaped pressure on the Supreme Court, which has a 6-3 conservative majority, to preserve tariffs that he has leveraged as a key economic and foreign policy tool.