The constitutionality of federal legislation sometimes turns on the presence and sufficiency of congressional findings of predicate facts, such as the effects of conduct on interstate commerce, state discrimination justifying the abrogation of sovereign immunity, or market failures justifying intrusions on free speech. Sometimes a congressional committee makes these findings in legislative history. Other times, Congress recites its findings in a statutory preamble, thus enacting its findings as law. Surprisingly, the Supreme Court has not distinguished between enacted and unenacted findings in deciding how much deference to accord congressional findings. This is striking because the difference between enactedness and unenactedness is so vigorously contested on questions of statutory interpretation, with textualists objecting to any reliance on legislative history and even purposivists conceding some risks. Both formal and functional considerations suggest that the enactedness line should be significant for constitutional questions as well. This is not because Congress has some comparative advantage in finding legislative facts more reliably than other governmental institutions, which is pervasively assumed but unrealistic. Rather, Congress's strongest claim for judicial deference is that legislative findings are highly normative and hence squarely within the legislative power. Recognizing this characteristic of modern fact--finding clarifies and strengthens the claim for deference--but only as to findings satisfying the constitutional requirements of bicameralism and presentment.
Crane, Daniel A. "Enacted Legislative Findings and the Deference Problem." Geo. L. J. 102, no. 3 (2014): 637.