In the summer of 1967 I worked as an intern in the office of the mayor of Detroit, and therefore was an eyewitness to the six-day riot that occurred in July and the official response thereto. Things got so bad that at one point I was, improbably, the third person in a meeting between Mayor Jerome Cavanagh and Governor George Romney.

From that experience I drew the following conclusion about why people riot when they do: they riot when they expect other people to do so. You only go out and loot and burn buildings and attack the unfortunate people in your way when you expect that you will have impunity because so many other people will be doing the same thing. The Detroit riot occurred soon after a riot earlier that month in Newark. Riots occurred, as predicted by my theory, in multiple cities after the murder of Martin Luther King in April 1968. After 1968 people stopped expecting riots, and there were none for many years. Rhetoric and news coverage prompted blacks in Los Angeles to expect a riot after the policemen accused of assaulting Rodney King were acquitted by a jury. But that riot lasted only 36 hours, and stopped after Governor Pete Wilson and Mayor Tom Bradley announced they had requested and would bring in 25,000 federal troops—far more than any mayor or governor considered asking for during the riots of the late 1960s.

The alternative theory to explain the riots was that they resulted from legitimate grievances. Blacks rioted in Newark, it was said, in protest against the policies of the white Mayor Hugh Addonizio. But blacks also rioted in Detroit, where Mayor Cavanagh had been elected in 1961 and 1965 with about 90% support from black voters. The policies he put in place were in line with liberal demands at the time. Indeed I argued that Detroit was immune from riots because of this. It turned out that I was wrong.

Fast forward 45 years. White House Press Secretary Jay Carney insisted on Friday that Muslims are rioting in many countries solely because of grievance: they’re protesting that video that almost no one has seen and which lay there somewhere in the Internet for some time without much protest. The riots and attacks were “not a response to United States policy and not obviously the administration or the American people,” Carney said, but “in response to a video, a film we have judged to be reprehensible and disgusting.” In this week’s Weekly Standard Lee Smith demolishes this argument and Stephen Hayes notes that the administration at first on Wednesday walked back the unauthorized Cairo Embassy statement condemning “the continuing efforts by misguided individuals to hurt the religious feelings of Muslims,” but then turned back to the grievance blame-the-video stance that Carney took on Friday.

Why the switch? Because the continued rioting undermines, perhaps fatally, one of the underlying premises of Barack Obama’s 2008 campaign and of his campaign now for reelection: that electing this man president will make the peoples of the world love America and Americans. I make a similar point in my as yet unpublished Sunday Examiner column, which should be accessible here when it goes online. The rioters in Cairo expressly reviled Obama and hailed Osama. They hate America and Americans. They hate our way of life and our freedoms. Obama’s election has made no difference; his campaign bragging about dispatching Osama bin Laden has perhaps got them hating us more. One powerful argument for reelecting him is being refuted by what we see on our television screens.

Will the rioting continue? My understanding is that Friday is the big day for Muslim riots, which start after people leave the mosque on the Muslim sabbath. So perhaps the rioting will taper off and not resume next week. Or perhaps it will continue, or resume next Friday. The key, in my view, is not whether Muslims are propitiated by our leaders’ denunciation of the video or the hamhanded attempts of our government to somehow suppress in a nation that has a First Amendment. The key is whether potential rioters expect others to riot. And gauging that, as I learned 45 years ago in Detroit, is hard for outsiders to do.