The key question in the Trump case is whether the 1977 International Emergency Economic Powers Act gives a president unfettered ability to set tariffs for any country, at any level, for as long as needed, whenever an emergency is declared at the president’s sole discretion.

Three lower courts have ruled illegal President Donald Trump's use of emergency powers to impose worldwide tariffs.

The Court will consider whether Donald Trump’s tariffs, which have roiled global markets and rankled America’s allies, are unconstitutional because the president imposed them unilaterally.