concurring.
I join the Court’s opinion, with one reservation which I deem called for by certain implications that might be drawn from the opinion.
As I stated in dissent in Shapiro v. Thompson, 394 U. S. 618, 658-663 (1969), I find no solid basis for the doctrine there expounded that certain statutory classifications will be held to deny equal protection unless justified by a “compelling” governmental interest, while others will pass muster if they meet traditional equal protection standards. See also my dissenting opinion in Katzenbach v. Morgan, 384 U. S. 641, 660-661 (1966). Except with respect to racial classifications, to which unique historical considerations apply, see Shapiro, at 659, I believe the constitutional provisions assuring equal protection of the laws impose a standard of rationality of classification, long applied in the decisions of this Court, that does not depend upon the nature of the classification or interest involved.
*490It is on this basis, and not because this case involves only interests in “the area of economics and social welfare,” ante, at 485, that I join the Court’s constitutional holding.