James P. Hoffa, the teamsters union boss who is under fire for using incendiary language against Republicans and the Tea Party, is the only son of Jimmy R. Hoffa, the most famous and controversial union figure in U.S. history.

Hoffa the son was 24 years old in 1975 when his father disappeared forever and presumably murdered.

Hoffa, the father, is believed to have been killed by members of the Mafia because he was insistent on taking over leadership of the Teamsters union after emerging from a prison sentence.

On July 30, 1975, Hoffa was last seen outside the Machus Red Fox Restaurant in Bloomfield Township, a suburb of Detroit, awaiting a meeting with two fearsome mobsters, Anthony ‘Tony Jack’ Giacalone of Detroit and Anthony ‘Tony Pro’ Provenzano, a labor union boss from New Jersey, who was affiliated with the Genovese crime family of New York City.

Hoffa was never seen again and his body was never found, although over the years rumors abounded about his fate and final resting place.

Prior to that fateful 1975 day, Hoffa had a very close working relationship with the mob, which had actively supported his leadership of the Teamsters.

In the process, Hoffa earned the enmity of Bobby Kennedy, who, as Attorney general of the U.S., vigorously prosecuted Hoffa and sent him to jail in 1964, following a conviction on charges of mail and wire fraud, jury tampering and conspiracy.

In a sensational and perhaps unexpected development, Hoffa was granted clemency in 1971 by President Richard Nixon. By that point, however, Frank Fitzsimmons was already entrenched as Teamsters boss -- and he was well liked by the Mafia because he was highly pliable and even-tempered (in contrast, Hoffa was pugnacious and volatile).

However, Hoffa retained a lot of loyalty among the rank-and-file members of the union, giving him hope he could retain his former position as union chief. Still, he had to wait five years to run for union office because federal laws forbade convicted felons from holding top union positions until five years after their release from prison.

Hoffa never got that far.

The saga of the Teamsters and Hoffa reflected an epic and decades-long intertwining and ever-shifting relationship between unions, mobsters and the highest levels of government. Hoffa, the bitter enemy of the Democrat Kennedys was later given his release by the Republican Nixon.

Hoffa’s son, the current Teamsters boss, is an avowed opponent of the Republican Party and embraces the Democrat Barack Obama (an ideological descendant of Bobby Kennedy, the man who Hoffa’s father hated more than anyone).