Pro-gun advocates have been telling us that gun laws dont prevent crime. My hometown, Baltimore, has a population of 637,000. Last year, homicides were down to a 20-year low, at 234 killings. My temporary hometown, London, is the largest city in Europe, at 7.5 million. Gun killings in 2008: seventeen. London has one tenth the shootings, with ten times the population. A citizen of Baltimore is a hundred times more likely to be shot to death, than a Londoner. Gun laws work.