You most likely know that the landmark 1954 Supreme Court decision Brown v. Board of Education ruled that racial segregation in U.S. public schools was unconstitutional. You may also know that the decision ordered states to desegregate “with all deliberate speed.”

Less talked about is the 1969 decision in Alexander v. Holmes County Board of Education, which, after years of obstruction by many states through the 1950s and 60s, ordered that racially segregated schools must immediately desegregate. In other words: You know what we said back in 1954? We actually meant it.

Some of the ramifications and subsequent events are captured in two complementary documentaries from the PBS “American Experience” series. “The Busing Battleground,” directed by Sharon Grimberg and Cyndee Readdean, explores the long buildup to and catastrophic results of busing in Boston, by which students were bused to schools outside their neighborhoods in an effort to desegregate the public school system….