Abbie Hoffman was an American political and social activist in the 1960s and 1970s. He was a leader of the counterculture movement and is best known for his role in the protests against the Vietnam War. He was also a co-founder of the Youth International Party, or Yippie, which was a radical left-wing organization that sought to bring about social change through protest and civil disobedience. Yippie Hoffman was a nickname given to him by his supporters.