U.S. Supreme Court Rules Maryland Tax Credit is Unconstitutional in Comptroller v. Wynne
On May 18, 2015, the United States Supreme Court issued a decision in Comptroller v. Wynne, holding that Maryland's personal income tax- which did not offer its residents a full credit for income taxes paid to other states on income they earned in those states - was unconstitutional. The majority opinion (5-4), authored by Justice Alito, held that the tax violated the dormant Commerce Clause because it discriminated against interstate commerce. Justices Scalia, Thomas, and Ginsburg authored dissenting opinions on varying grounds.