JUSTICE O'CONNOR, concurring.
I join the Court's opinion holding that, "[i]n light of the facially discriminatory nature of the multiple activities exemption," ante at 483 U. S. 244, see Maryland v. Louisiana, 451 U. S. 725, 451 U. S. 756 -757 (1981), the Washington taxpayers need not prove actual discriminatory impact "by an examination of the tax burdens imposed by other States." Ante at 483 U. S. 247. I do not read the Court's decision as extending the "internal consistency" test described in Armco Inc. v. Hardesty, 467 U. S. 638, 467 U. S. 644 -645 (1984), to taxes that are not facially discriminatory, contra, post at 483 U. S. 257 -258 (SCALIA, J., concurring in part and dissenting in part), nor would I agree with such a result in these cases. See American Trucking Assns., Inc. v. Scheiner, post p. 483 U. S. 298 (O'CONNOR, J., dissenting).