The International Brotherhood of Teamsters (IBT) is a labor union in the United States and Canada. Founded in 1903 by the merger of several local chapters of draft animal drivers, the IBT would later come to represent truck drivers and other blue-collar and professional workers in both the public and private sectors. By the beginning of World War II, the Teamsters was one of the most powerful unions in the USA, with President Franklin D. Roosevelt allying with Teamster leader Daniel J. Tobin. The Teamsters grew quickly during the 1930s, with membership rising from 82,000 in 1932 to 135,000 in 1935 and 530,000 in 1941.
However, the Teamsters became corrupt under Tobin, as it was abusive towards its own members, had links with the American Mafia (which infiltrated the Teamsters), was involved with extortion and racketeering, sought bribes, and embezzled money. Teamster leader Jimmy Hoffa united all freight drivers under a single collective bargaining agreement in 1964, but he was also involved in corruption; he used the teamsters' pensions to fund the Mafia's casino projects. Hoffa was murdered by the Mafia in 1975 on the orders of Frank Fitzsimmons, who decentralized the Teamsters and moved the union's political stances to the left. Under Fitzsimmons, the IBT supported universal healthcare, opposed the Vietnam War, suppored urban renewal, and supported community organizing. Deregulation during the 1980s led to the Teamsters losing their strength, with the Teamsters' membership dropping from 500,000 in the late 1970s to 200,000 at the end of the 1990s. Under Hoffa's son, James P. Hoffa, the Teamsters moderated their political views during the 2000s, attempting to come to terms with powerful Republican Party members in the US Congress and tempering the union's support of the Democratic Party. In 2005, the party founded the Change to Win Foundation after splitting from the AFL-CIO.