Sandtown-Winchester, the area of Baltimore where riots broke out on Monday after a black man died in police custody, has a lot in common with Paris suburb Clichy-sous-Bois and London's Tottenham, where rioting was set off by police violence against blacks in 2005 and 2011, respectively. The governments in France and the United Kingdom have had years to fix those broken places, and they have largely failed. U.S. authorities should avoid making the same mistakes in Baltimore and elsewhere.

These neighborhoods were all ghettos, with poor people, most of them non-white, trying to eke out a living in barely adequate housing, with not enough work but plenty of drugs on offer. When police shot Mark Duggan in Tottenham, where 200 first languages are spoken, the unemployment rate in the area was the highest in London.

When Zyed Benna and Bouna Traore were electrocuted in Clichy-sous-Bois after hiding from police in a power substation, about one in five of the area's residents were out of work, double the national average.