A ruling against Trump could restrict presidential authority to impose tariffs and limit future administrations’ flexibility in trade negotiations, while a ruling in his favor would affirm broad executive control over U.S. trade policy, potentially redefining the scope of presidential power for decades to come.

President Donald Trump has worked fast in his second term, wielding unilateral power to reassert American dominance in the global economy. For a few hours Wednesday, the world will get clues as to whether any US institution is willing to rein him in.