With the 10th anniversary of the Columbine High School massacre approaching, communities across the nation have relived the horror of what happens when evil, paranoia and madness mix with the ready availability of guns.

An appalling series of eight mass shootings has claimed at least 57 lives in recent weeks. On Saturday, three Pittsburgh police officers were slain by a man wielding an AK-47. The day before, a suicidal gunman took the lives of 13 civilians in Binghamton, N.Y., before shooting himself. Domestic disputes led to other massacres in which children were cut down.

Experts believe the nation's economic woes are a factor underlying some of the latest violence. But easy access to fearsome arsenals enables killers to wreak carnage when they snap.

With 280 million weapons available in the country, it's little wonder guns account for roughly 12,000 of the 17,000 people murdered each year.

As the nation did after the April 20, 1999, Columbine murders, it is time to confront the many causes of gun violence.

But the starting point has to be stricter gun control measures including a national assault-weapon ban, wider reporting of lost and stolen guns, universal background checks, and limits on handgun purchases.

For local police to have any hope of fighting illegal gun sales, Congress also must repeal the Tiahrt Amendment that shields traffickers by limiting gun traces.

The question is whether the latest shootings will budge the needle on a public policy debate that has been stalemated for years.

Until now, the Obama administration has failed to take on the National Rifle Association over even the most reasonable gun control measure. Granted, Team Obama has been busy on other fronts, but that's hardly a tenable stance now.

Attorney General Eric H. Holder Jr. in February took aim at what should be the top priority: reinstating a tough, federal assault-weapon ban. Until the ban lapsed in 2004, it safeguarded police from 19 military-style weapons for a decade.

There's other unfinished business, too: turning down the volume on the increasingly reckless drumbeat from right-wing groups over a so-called "Second Amendment Revolution."

The fear ascribed to Pittsburgh's 23-year-old cop-killer suspect that President Obama was about to ban guns isn't all that surprising, given some gun-rights rhetoric. As the CeaseFirePA gun control group asked this week, "At what point does super-heated rhetoric about government coming to take your arms turn into a toxic brew that puts some misguided loner packing guns ... over the edge?"

The debate should be about how to stop senseless shootings.