When we consider, for a moment, that all South Dakota would lose if she adheres to her chosen course as to a suitable minimum drinking age is 5% of the funds otherwise obtainable under specified highway grant programs, the argument as to coercion is shown to be more rhetoric than fact. As we said a half century ago in Steward Machine Co. v. Davis:
"[E]very rebate from a tax when conditioned upon conduct is in some measure a temptation. But to hold that motive or temptation is equivalent to coercion is to plunge the law in endless difficulties. The outcome of such a doctrine is the acceptance of a philosophical determinism by which choice becomes impossible. Till now, the law has been guided by a robust common sense which assumes the freedom of the will as a working hypothesis in the solution of its problems."
301 U.S. at 301 U. S. 589-590.
Here Congress has offered relatively mild encouragement to the States to enact higher minimum drinking ages than they would otherwise choose. But the enactment of such laws remains the prerogative of the States not merely in theory, but in fact. Even if Congress might lack the power to impose a national minimum drinking age directly, we conclude that encouragement to state action found in § 158 is a valid use of the spending power. Accordingly, the judgment of the Court of Appeals is
Affirmed.