The U.S. Supreme Court interprets constitutional law through judicial review, which allows it to evaluate the constitutionality of laws and actions by legislative or executive branches. The justices apply various theories such as textualism, originalism, and living constitutionalism to reach decisions. They consider the text, historical context, and evolving societal values in their rulings. Landmark cases often set important precedents that guide future interpretations and practices regarding individual rights and government powers within the legal framework of the Constitution.