Madison is the first of many important opinions issued by Marshall. It set a precedent for the use of "judicial review," the Supreme Court's power to determine whether a law is constitutional or unconstitutional. Although the idea of ​​judicial review was not new at the time, the Marbury decision helped establish the role of the judiciary and spelled out the role of the Supreme Court within the structure of the U.S. government. At the same time, Marshall's opinion appeared impartial to the political aspects of the case, attempting to demonstrate that politics should not interfere with legal decisions. His thinking in relation to understanding the case stems from his belief that the federal judiciary must protect citizens from excessive intervention by state governments, which can be done by declaring laws enacted by state governments.