Which entity holds the ultimate authority over conflicts arising between states?

The U.S. Supreme Court holds the ultimate authority over conflicts arising between states due to its role as the highest court in the federal judiciary. This authority is rooted in the Constitution, particularly in Article III, which establishes the Supreme Court's jurisdiction to hear cases that involve disagreements between states. The importance of this function lies in maintaining the rule of law and resolving disputes that could lead to conflict or varying interpretations of law across state lines.

By adjudicating these conflicts, the Supreme Court ensures a unified legal framework that applies equally to all states, thereby promoting national coherence and stability. This is crucial for upholding the principles of federalism, where both the national and state governments have distinct powers but must operate within a structured legal context.