In the case of Melene James v. City of Boise, Idaho et al., 2015, the U.S Supreme Court ruled that state courts cannot ignore federal law when it comes to awarding legal fees in civil rights cases. The dispute began when Melene James and other plaintiffs sued the city of Boise for violating their constitutional rights but lost. Subsequently, they were ordered by Idaho courts to pay the city's legal costs based on an Idaho rule allowing defendants (in this case, Boise) to collect attorney’s fees from unsuccessful plaintiffs in civil rights litigation - a rule contrary to federal law which only allows such fee-shifting if plaintiff's action was "frivolous, unreasonable or without foundation". The Supreme Court unanimously reversed this decision stating that while states have leeway in structuring their own laws and court systems; they can't disregard national rules under supremacy clause.

In the dissenting opinion for MELENE JAMES v. CITY OF BOISE, IDAHO, et al., Justice Thomas, joined by Justice Scalia, disagreed with the majority's decision to deny Idaho courts' interpretation of state law under the doctrine of sovereign immunity. The dissent argued that it was not within the Supreme Court’s jurisdiction to correct a state court’s interpretation of its own laws unless there is a federal issue involved. They contended that this case did not present such an issue and thus should have been left in the hands of Idaho courts. Furthermore, they expressed concern over potential violations of federalism principles if states were denied their right to interpret their own statutes independently.