Fifty years ago Wednesday a black taxi driver in Newark, N.J., named John Smith was stopped shortly after dusk by two white police officers for a traffic violation. The officers later said that Smith, who was driving with a suspended license, became profane and abusive. Bystanders countered that the cops physically attacked him without provocation. Smith suffered a broken rib during the encounter and was taken to the local precinct, charged with assault and resisting arrest, and put in a holding cell. But rumors spread quickly that he had been killed by the police.

Over the next four days, Newark experienced one of the worst riots in U.S. history, resulting in 26 deaths, more than 700 injured, nearly 1,500 arrests and damage to some 1,000 businesses. Subsequent journalistic accounts and government reports on the causes of the disorder would cite racism, segregation, economic distress, deindustrialization and police misconduct—the same explanations offered for more recent racial unrest in places like Ferguson Mo., and Baltimore. Those factors almost certainly have played a role, but they also don’t tell the whole story.

Recall that the Newark riots were preceded by those in the Watts section of Los Angeles two summers earlier, when 34 people died, 4,000 were arrested, and more than 1,000 stores were looted or seriously damaged. Yet Watts was no Newark. It was full of single-family homes, not housing projects. In the mid-1960s, the Los Angeles economy was expanding and blacks had access to good jobs. Just a year before Watts went up in flames, the National Urban League, a black civil-rights organization, released a survey of 68 cities in the U.S. where blacks were prospering. L.A. topped the list.

The 1967 Detroit riots, which began only a week after Newark’s ended, also complicate the popular explanations of economic deprivation and “black rage.” The black unemployment rate in Detroit at the time was 3.4%, lower than the jobless rate for whites nationally. The black poverty rate in Detroit was half that of blacks nationally, and the homeownership rate among blacks in the Motor City was one of the highest in the nation. The city had a large and growing black middle class and the smallest black-white income gap in the country.

Today’s black leaders and their liberal sympathizers in the media like to attribute a political consciousness to ghetto rioters, but a previous generation of black activists had a less romantic view. In his 1968 book, “The Unheavenly City,” Edward Banfield writes: “Most civil rights leaders dismissed the idea that the riots were conscious protests; that was not merely an after-the-fact rationalization, Kenneth B. Clark said, it was an ‘independent of the fact’ one.” Bayard Rustin saw more opportunism than activism on display in the rioting: “They riot either out of sheer cussedness or for criminal reasons, and in some instances because mob action seems to be taking on the aspects of a fad. . . . Bedevil the police, strip stores, shout and yell, crush anyone who opposes you . . . and if the police try to stop it, just yell ‘brutality.’ This is the pattern.”