The parties have come a long, strange way from Booker T. Washington and Vito Marcantonio to Clarence Thomas and Antonin Scalia. This from Thaddeus Russell’s A Renegade History of the United States:
Guglielmo's analysis of voting patterns in Chicago during the 1920s shows that “many Italians willingly voted alongside African-Americans throughout these years.” Furthermore, “some Italians never seemed overly concerned about belonging to the same party [Republican] as African Americans, even when the Democrats furiously fought to paint that party as ‘Negro’ through and through. Indeed, Italian-language newspapers openly advertised the point that Italians and African-Americans held similar party affiliations, and on one occasion, L’Italia held up African-Americans as a model for Italian political organization and behavior.”
When the national political parties were demographically realigned in the 1930s, both Italian Americans and African Americans moved overwhelmingly to the Democratic Party and remained solid voting blocks for the Democrats for the next 30 years. Indeed, one of the greatest champions of black civil rights during the 1930s and 1940s was Vito Marcantonio, the left-wing New York Congressman whose East Harlem district contained large numbers of both Italians and African Americans. Marcantonio sponsored several civil rights bills, led the congressional fight against the discriminatory poll tax in southern states, and worked to make lynching a federal crime.