"The Congress shall have power ... to regulate commerce with foreign nations, and among the several States, and with the Indian tribes." This clause otherwise known as the commerce clause, gives Congress broad powers to set tariffs and insure the unimpeded flow of interstate commerce. The primacy of the federal government to regulate commerce was decided in the 1824 Supreme Court case, Gibbons v Ogden. At the time the Constitution was written, the Indian tribes were considered foreign nations.."
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The power to regulate commerce was one of the most important powers granted to the Federal government and was one of the key reasons that the Constitution and the Federal government was established. Congress and not the President was granted this authority.