The Watts uprising was a harbinger of things to come.

Ignited 50 years ago on Aug. 11, 1965, the Watts rebellion still challenges all Americans to consider whether the nation has made the progress that has been easily symbolized but rarely realized in the movement for equal justice under the law. With Ferguson, Missouri, locked down in its second state of emergency on the anniversary of a white police officer killing Michael Brown, an unarmed black teenager, the possibility of progress over a half-century arc remains in doubt.

Serious reflection on the rebellion, the biggest U.S. black uprising since the era of slavery, should rightly disrupt the joyous commemorations of the 1965 Voting Rights Act and other Great Society advances. Because it forces the nation to wrestle with continuing civil rights problems and examine the terrible legacy of police brutality in black communities. The systemic concentrated poverty and police oppression that triggered the rebellion still marks the United States — from Ferguson to Baltimore.