Watch "Fareed Zakaria GPS," Sundays at 10 a.m. and 1 p.m. ET on CNN



The Civil Rights Act remains one of the great puzzles and achievements of American history. The achievement part is obvious. The puzzle part is two-fold. First: why did it take so long? It passed 101 years after President Lincoln's Emancipation Proclamation. And second: how did it finally get passed?

To get the answers, let’s step back 50 years. It's hard for young people today to imagine, but back then there were restaurants and stores and cabs – mostly in the South – where black people were not served. There were separate water fountains for the two races and, as Rosa Parks made infamous, separate sections of buses, just to name a few. It was legal in 1964 to refuse to hire somebody because of the color of their skin or their gender. A year earlier, President John F. Kennedy had addressed the nation to urge action on civil rights.

But then Kennedy was assassinated. Surprisingly, his successor Lyndon Baines Johnson, a staunch Southerner, took up the cause, a cause that looked hopeless.

Why? Johnson biographer Robert Caro explains.

For more on the issue, tune into CNN's 'The Sixties' as it explores the civil rights movement in-depth, this Thursday at 9 p.m. ET/PT.

