The challengers, businesses and 12 Democrat-led states, have contended that tariff power lies with Congress under the Constitution, not the president.
The administration argues that the tariffs, which have generated approximately $89 billion in revenue between February and September, address national emergencies including trade imbalances and drug trafficking.Trump has pressed the Court, dominated by a 6-3 conservative majority, to uphold his use of IEEPA and maintain his tariff regime.
At issue is the major questions doctrine,
under which executive actions with sweeping economic and political implications require clear congressional authorization. Lower courts found the administration’s interpretation of IEEPA inadequate under that standard.
If the Supreme Court invalidates the tariff programme under IEEPA, the government could face enormous refund liabilities and the broader question of how far the president can act in trade and economic policy without Congress.

