John Marshall was an American statesman, lawyer, and Founding Father who served as the fourth chief justice of the United States from 1801 until his death in 1835. In 1801, President John Adams appointed Marshall to the Supreme Court. Marshall quickly emerged as the key figure on the court, due in large part to his personal influence with the other justices.
The 1803 case of Marbury v. Madison presented the first major case heard by his court. In his opinion for the court, Marshall upheld the principle of judicial review, whereby courts could strike down federal and state laws if they conflicted with the Constitution. Marshall’s holding avoided direct conflict with the executive branch, which was led by Democratic-Republican President Thomas Jefferson. By establishing the principle of judicial review while avoiding an inter-branch confrontation, Marshall helped implement the principle of separation of powers and cement the position of the American judiciary as an independent and co-equal branch of government.