Jimmy Hoffa IBT would expand as the union itself grew. Hoffa worked to defend the Teamsters unions from raids by other unions, including the CIO, and extended the Teamsters' influence in the Midwestern states, from the late 1930s to the late 1940s. Although he never actually worked as a truck driver, he became president of Local 299 in December 1946. He then rose to lead the combined group of Detroit-area locals shortly afterwards, and advanced to become head of the Michigan Teamsters groups sometime later. During this time, Hoffa obtained a deferment from military service in World War II by successfully making
Jimmy Hoffa his younger brother Robert F. Kennedy as Attorney General. Robert Kennedy had been frustrated in earlier attempts to convict Hoffa, while working as counsel to the McClellan subcommittee. As Attorney General from 1961, Kennedy pursued the strongest attack on organized crime that the country had ever seen, and he carried on with a so-called "Get Hoffa" squad of prosecutors and investigators. In 1964, Hoffa was convicted in Chattanooga, Tennessee of attempted bribery of a grand juror, and was sentenced to eight years. This case resulted from an earlier matter, the Test Fleet case, the trial for which had been held