William Hubbs Rehnquist (October 1, 1924 – September 3, 2005) was an American lawyer, jurist, and political figure who served as an Associate Justice of the Supreme Court of the United States and later as the 16th Chief Justice of the United States. Considered a conservative, Rehnquist favored a conception of federalism that emphasized the Tenth Amendment's reservation of powers to the states. Under this view of federalism, the Supreme Court of the United States, for the first time since the 1930s, struck down an Act of Congress as exceeding its power under the Commerce Clause. Rehnquist served as Chief Justice for nearly 19 years, making him the fourth-longest-serving Chief Justice after John Marshall, Roger Taney, and Melville Fuller, and the longest-serving Chief Justice who had previously served as an Associate Justice. The last 11 years of Rehnquist's term as Chief Justice (1994–2005) marked the second-longest tenure of a single unchanging roster of the Supreme Court, exceeded only between February 1812 and September 1823. He is the eighth longest-serving justice in Supreme Court history.