The common denominator in all cities: guns. About two thirds of murders nationwide are committed with firearms, compared with about one quarter a generation ago. And the guns are more deadly. In urban areas, semiautomatics have replaced Saturday night specials as the weapon of choice. “The new guns tear your insides out,” says Chicago Chief of detectives John Townsend. The result: more deaths from wounds and errant shots. Meanwhile, pressure from the National Rifie Association and foot-dragging by Congress has stalled national legislation banning assault weapons–despite support from police, the public and even gun owners.

Police say killers have also become more vicious, often firing after trivial provocations. In Houston on Memorial Day, 29-year-old Alfred Rodgers killed his brother after arguing over a piece of holiday ham. Last March in Boston, gang members gunned down a mother of five after setting her apartment on fire to “smoke out” her son, their original target. Gunmen often don’t show remorse for bystanders caught in the cross-fire. “Now they call those innocent victims ‘mushrooms,’ meaning they get underfoot, so you trample them,” says Thomas Reppetto, president of the Citizens Crime Commission of New York City.

Politicians tend to blame the recent increases on the cocaine epidemic. That may be valid in drug centers like Washington, D.C., Miami and Los Angeles, but the theory doesn’t hold up across the country. In Chicago, domestic problems, not drugs, are at the heart of most murders. In Milwaukee, murders are up 16 percent this year, even though drug-related homicides have decreased. Police in Indianapolis, hardly a crack-ridden city, have also recorded a recent upsurge in violent murder.

If policymakers blame drugs, sociologists point to everything from mayhem on TV to the breakdown of the urban family. “We’re seeing more and more kids growing up in hopeless situations choosing violence,” says Edward Loughran, commissioner of the Massachusetts Department of Youth Services. “Their own life, or someone else’s life, means nothing to them.” Police on the front lines have a simpler explanation: “The immediate problem is the availability of firearms in general,” says Boston Police Commissioner Francis M. Roache. “It’s time for this country to face up to the fact that we are a violent society.”