Which court holds ultimate authority in the United States?

The U.S. Supreme Court holds ultimate authority in the United States because it is the highest court in the federal judiciary system. Its decisions are final and binding across the country, meaning that lower courts, including district and circuit courts, must follow the legal precedents set by the Supreme Court. The U.S. Supreme Court has the power to review cases from state supreme courts and federal courts, which allows it to interpret the Constitution and federal laws, thereby shaping the legal landscape of the nation. This authority establishes it as the final arbiter of legal disputes and constitutional questions, solidifying its role as the pinnacle of the judicial system.