William J. Brennan, Jr.

“ We reverse and remand to the District Court for decision on the merits of appellants' Fourteenth Amendment claims.
There are fundamental objections to any conclusion that a litigant who has properly invoked the jurisdiction of a Federal District Court to consider federal constitutional claims can be compelled, without his consent and through no fault of his own, to accept instead a state court's determination of those claims. ”

“ Thus mere compliance with Windsor will not support a conclusion, much less create a presumption, that a litigant has freely and without reservation litigated his federal claims in the state courts and so elected not to return to the District Court.
We recognize that in the heat of litigation a party may find it difficult to avoid doing more than is required by Windsor. This would be particularly true in the typical case, such as the instant one, where the state courts are asked to construe a state statute against the backdrop of a federal constitutional challenge. ”

“ The case does not mean that a party must litigate his federal claims in the state courts, but only that he must inform those courts what his federal claims are, so that the state statute may be construed 'in light of' those claims. ”