Gorton defeated three other candidates for the Liberal leadership after Harold Holt's disappearance on 17 December 1967. He became the first and only senator to assume the office of Prime Minister, but soon transferred to the House of Representatives in line with constitutional convention. The Gorton Government continued Australian involvement in the Vietnam War, but began withdrawing troops amid growing public discontent. It retained office at the 1969 federal election, albeit with a severely reduced majority. Gorton's domestic policies, which emphasised centralisation and economic nationalism, were often controversial in his own party, and his individualistic style alienated many of his Cabinet members. He resigned as Liberal leader in 1971 after a confidence motion in his leadership was tied, and was replaced by William McMahon.