[2] After getting to know the three Trotskyist Dunne brothers, (Miles, Vincent and Grant) and Swedish socialist Carl Skoglund, he joined the Communist League of America.

He was influential in the Teamsters' shift from emphasis on local delivery work to over-the-road traffic, which keyed their great expansion towards becoming the largest union in the United States.

Dobbs primarily inspired Hoffa with his view that the capitalist system was a Darwinian struggle, where power, rather than morality, was the primary factor determining the eventual outcome.

[4] For opposing World War II, he and other leaders of the SWP and the Minneapolis Teamsters were convicted of violating the Smith Act, which made it illegal to "conspire to advocate the violent overthrow of the United States Government".

The two American Trotskyists decided to fully support the Cuban Revolution and the leadership of Fidel Castro and Che Guevara.