Article 1, Section 8 of the Constitution gives Congress, not the president, the power to “lay and collect Taxes, Duties, Imposts, and Excises.” Tariffs traditionally fall within that legislative domain, and any bill raising revenue must originate in the House of Representatives.

President Donald Trump won't be going in person to the Supreme Court hearing Wednesday that will determine the fate of the tariffs at the heart of his economic and foreign policy -- but his treasury s...