Regulation of Interstate Commerce What standard initially was used by the Supreme Court in interpreting the phrase \"commerce amoung the several states\"? Solution During the post-1937 era, the use of the Commerce Clause by Congress to authorize federal control of economic matters became effectively unlimited. Since the latter half of the Rehnquist Court era, Congressional use of the Commerce Clause has become slightly restricted again, being limited only to matters of trade or any other form of restricted area (whether interstate or not) and production (whether commercial or not)..