From the 1930s to the early 1960s civil rights law was made primarily through constitutional litigation. Before Rosa Parks could ignite a Montgomery Bus Boycott, the Supreme Court had to strike down the Alabama law which made segregated bus service required by law; before Martin Luther King could march on Selma to register voters, the Supreme Court had to find unconstitutional the Southern Democratic Party's exclusion of African-Americans; and before the March on Washington and the Civil Rights Act of 1964, the Supreme Court had to strike down the laws allowing for the segregation of public graduate schools, colleges, high schools, and grade schools.