What if we had a mass shooting and nobody noticed?

That gloomy thought came to mind as I listened to the unsettling sound of silence that followed the September 16 Navy Yard shooting in the nation’s capital that killed 12 people, plus the shooter.

Three days later it came to mind again as a shooting spree in Chicago’s Back of the Yards neighborhood made national news. Thirteen were injured, including a 3-year-old boy who was shot in the face. Four people have been charged in the reportedly gang-related incident.

President Obama eloquently expressed the grief, outrage and frustration that every decent American should feel about “yet another mass shooting” at the Navy Yard.

But overall reaction to the workplace slaughter by a reportedly deranged gunman was sadly and noticeably subdued compared to the national outrage that reignited the national gun debate following the massacre of 20 children and six educators in Newtown, Connecticut.

That’s because after all the anguish, debate and proposed legislation that emerged from the Newtown tragedy, the legislation was voted down in the Senate and everyone returned to other matters — like House Republicans voting uselessly to repeal Obamacare more than 40 times. Opposition to even modest measures was too strong, especially from rural centers of pro-gun culture.

If even the massacre of children and the shooting of then-Rep. Gabrielle Giffords, an Arizona Democrat, could not move Congress to pass new gun safety measures, it’s no wonder that the energy for gun safety seems to have drained out of Capitol Hill.

But that doesn’t mean that we Americans can’t do anything but wring our hands over the continuing carnage. As even mass shootings lose their ability to shock us, both sides of the gun debate need to face a bracing reality: The gun violence problem is not only local and it’s not only about guns.

Those points were urgently expressed by New Orleans mayor Mitch Landrieu and Philadelphia mayor Michael Nutter in a joint speech in Washington last Thursday. They called for a new “surge” in attention and national action to the “virus” of gun-related violence.

Calls for national action are hardly new, but I was encouraged by the mayors’ refusal to be, as Landrieu put it, bogged down by the “seemingly mind-numbing debate about gun control.”

Instead they emphasized remedies everyone should be able to agree on. They included more cops on the street, as in a stronger COPS program — Community Oriented Policing Services — passed by Congress under President Bill Clinton; stronger cooperation with the federal government to target criminals with illegal guns and stronger measures against straw purchases and interstate gun traffickers.

Yet the two mayors also called for more personal responsibility and engagement by parents, pastors, coaches and neighbors. “Babies having babies just doesn’t work,” Landrieu said.

I’ve heard Chicago’s Mayor Rahm Emanuel, who reportedly left some scheduled meetings with members of Obama’s cabinet in Washington early after hearing of the mass shooting back home, express a similar agenda in his slogan: “Policing, prevention, penalties and parenting.”

Bottom line: A problem as complex as urban violence must be pushed back the same way it emerged: in every sector of community and political life.

But first we have to care. Citing the number of black men killed by homicide in his city in 2012, Nutter observed: “If the Ku Klux Klan came to Philadelphia and killed 236 black men, the city would be on lockdown.”

The same would be true if “international terrorists killed 236 Philadelphians of any race,” he said. “And, yet, 236 African-American men murdered in one city — not one word. No hearings on the Hill, no investigations … nothing but silence.”

We need to end the sound of silence. It was easier to take national political action in the ’90s. The economy was doing well and Congress was not as fiercely divided as it is today. But, as the two mayors said in Washington, we should not be more willing to pay for safe streets in Afghanistan than to make our streets safer at home.

(Email Clarence Page at cpage@tribune.com.)

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