William Hubbs Rehnquist (October 1, 1924 – September 3, 2005) was an American lawyer and jurist who served on the Supreme Court of the United States for 33 years, first as an associate justice from 1972 to 1986, and then as the 16th chief justice from 1986 until his death in 2005. 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.