Robinson's major league debut brought an end to almost sixty years of segregation in professional baseball, known as the baseball color line. After World War II, several other forces were also leading the country toward increased equality for blacks. This included more African-Americans moving to the North, where their political influence grew. President Harry Truman's desegregation of the military occurred in 1948. Robinson's breaking of the baseball color line and his professional success symbolized these bigger changes and showed that the fight for equality was more than simply a political matter. Martin Luther King, Jr. said that he was "a legend and a symbol in his own time", and that he "challenged the dark skies of intolerance and frustration." According to historian Doris Kearns Goodwin, Robinson's "efforts were a monumental step in the civil-rights revolution in America ... [His] accomplishments allowed black and white Americans to be more respectful and open to one another and more appreciative of everyone's abilities."