What developments in American society helped to make the racial revolution of the 1950s and 1960s possible?

Answer 1

As we became more urbanized in the middle 20th century, we also came into closer contact with people of other ethnic backgrounds.

Also, consider these events.

"1943 -- War contractors barred from racial discrimination.

Riots in Harlem, Detroit.

1948 -- President Truman issues executive order outlawing segregation in U.S. military.

1952 -- Racial, ethnic barriers to naturalization removed by Immigration and Naturalization Act."

http://www.cnn.com/EVENTS/1997/mlk/links.html