Though widely acknowledged to be very smart, this Justice aroused deep and often vituperative ideological hostility. He was appointed by a President as part of the President's campaign to move the Court towards more judicial restraint -- and, in keeping with his general tendency of mostly deferring to government action, this Justice was willing to endorse considerable federal government authority under the Commerce Clause, for instance letting the government regulate the growing of things for personal consumption on the theory that such regulation was necessary and proper to the regulation of interstate commerce.
But the Justice also believed that there were important limits on federal authority: "The exercise of the commerce power may . . . destroy state sovereignty." If the power is read too broadly, "the National Government could devour the essentials of state sovereignty, though that sovereignty is attested by the Tenth Amendment."
Therefore, the Justice reasoned, Congress's power under the Commerce Clause must have judicially enforceable limits. In other opinions, he took similar views, stressing the Tenth Amendment as a limit on other Congressional powers, and finding in the constitutional structure limits to the federal government's ability to interfere with state government functions. This Justice was . . .
William O. Douglas, the noted liberal and Roosevelt appointee. The quotes are from Justice Douglas's opinion in Maryland v. Wirtz (1968); the two cases I later refer to are United States v. Oregon (1961) and New York v. United States (1946). The personal consumption of crops case is Wickard v. Filburn (1942).