It has been a bad week in the United States in a bad year marked by remarkable international turmoil. The recession and  high unemployment persist at a time when the powerless seemed poised to fight back, creating a recipe for insurrection—as happened first  in the Middle East and now in Great Britain.

According to Wednesday’s (August 9) Washington Post editorial, “the common factors [sparking the riots] include high unemployment, resentment toward a prosperous and seemingly impenetrable upper class, and hatred of the police.”

All that sounds only too familiar, so should the United States expect riots here next? Are recent instances of mob violence in Philadelphia, Milwaukee, and Montgomery County, Maryland  leading edges of a  wave of violence here?

I think the answer is probably not, at least not on the scale of what has happened in London.

First, a few facts about riots. They are exceedingly rare events, and like all rare events exceedingly hard to predict.  There’s little formal research on what causes or comes with riots.  They seem to be more likely when the economy is sour, but aren’t in sync with larger crime trends – notably, the decline  in violent crime here and  in the UK.

And, a critical incident with police, such as the police shooting in South London, is often the spark that ignites. Look at Washington, DC. It has seen two waves of rioting – the first in 1968 after Martin Luther King Jr., was assassinated, and then again in Mount Pleasant in 1991. (In both cases, the White House was just two or three miles away.) Of the two, the Mount Pleasant riots were closer to what’s going on now in the UK.

On May 5, 1991, Washington, DC police confronted a group of Hispanics drinking alcohol outside their homes. A minor but poorly handled confrontation blew up when police shot an unarmed man (look here for a riveting blow by blow account).

Despite calls for calm from leading civil rights activists, Mount Pleasant exploded in a wave of violence.  The city’s response, however, is what makes me optimistic about today’s situation.  DC basically acknowledged that the rioters’ complaints—a police force insensitive to cultural differences when dealing with recent immigrants and too few resources to meet these newcomers’ needs—were valid.

Since then, DC’s government has made headway against both these problems a priority. It  has  improved at-risk communities, adopted community policing, created more humane and rehabilitative juvenile justice systems, and applied effective programs to divert drug- involved offenders to treatment instead of prison,  among many other initiatives.  Though imperfect –many moves  have been responses to critical incidents, not staples of a long-term strategic plan–overall, local government has been working to help address the problems of those on the bottom rungs of the socioeconomic ladder.

Another substantial US/UK difference  is that the US is much more of a police state than the UK. While the UK’s police force is shrinking, the number of sworn officers per US citizen has held steady, growing along with the US population for three decades.  Since the number of prisoners in the US has quadrupled since 1980, the UK’s incarceration rate is only about one-fifth of ours. Heavy policing costs a lot, but it does leave the US better prepared for emergencies, including riots.

That said, the London rioters seem to defy many stereotypes, which should give us pause.  The UK rioters are multi-racial and appear to encompass middle class and poor residents alike. While anger over  social service cuts is often named as a cause of the riots,  closer to the whole truth might be this take from Richard Sennett and Saskia Sessen in the August 11^th New York Times: “the rioters seem motivated by a more diffuse anger, behaving like crazed shoppers on a spree.” This sounds more like Philadelphia’s  flash mobs in 2011 than the Watts rioters in 1965.

At day’s end, the question is how much we are willing to spend to protect ourselves against a potentially high cost event that is unlikely to happen.  I wish I felt less sure that in today’s super-charged political atmosphere we’re unlikely to get the open and honest discussion needed to answer it well before push comes to shove.