If more lowlifes got the message that gun trafficking in Philadelphia would earn them years behind bars, maybe city streets would be less dangerous for brave officers like slain Police Sgt. Patrick McDonald.

That message - along with a measure of justice - was delivered loud and clear this week.

A federal jury convicted the man who transported the illegal handgun used by an ex-con to kill McDonald during a September 2008 traffic stop in North Philadelphia. When sentenced in March for violating weapons laws, Stephen Lashley, 33, could face up to five years in prison.

In the hands of just-paroled Daniel Giddings, the .45-caliber weapon Lashley purchased illegally for cash and marijuana proved lethal when turned on the 30-year-old police sergeant. Giddings also used the pistol to shoot at other officers before being gunned down and killed by police.

Kudos to agents from the Bureau of Alcohol, Tobacco, Firearms, and Explosives who tracked the weapon. But the route of the gun into the hands of a killer proved all too common: Lashley, barred from owning a gun because of an earlier drug conviction, bought it from a man who purchased the gun legally in South Carolina. Lashley brought it to Philadelphia and, eventually, it came into Giddings' possession.

For years, guns used in crimes across the city and in Camden have been funneled to both towns' worst neighborhoods in much the same way.

Federal authorities working with Philadelphia District Attorney Lynne M. Abraham and state Attorney General Tom Corbett have been doing a good job lately of breaking up that supply chain. The Lashley prosecution is a high-profile example, but so-called straw buyers like Lashley have been getting convicted in federal court on a fairly regular basis.

While good work by police and prosecutors is critical to fighting trafficking, there's also a major role yet to be played by Pennsylvania lawmakers in enacting tighter gun laws. All they have to do is listen to law enforcement officers and local officials in 160 communities - instead of pledging allegiance to the National Rifle Association.

Police, prosecutors, and community leaders simply want lawmakers to require the reporting of lost and stolen weapons. The statute would give authorities another weapon to pursue gun traffickers, who often claim guns are lost or stolen as a cover story.

Along with Philadelphia, 16 communities have passed their own version of this law in an effort to nudge the state into action. The western community of Aliquippa became the latest to do so last week - ironically, it's only an hour's drive from Penn Hills, where a police officer, Michael Crawshaw, 32, was shot and killed Sunday. His alleged assailant is a career criminal authorities contend used an illegal weapon.

The Crawshaw shooting prompted a gun control group, CeaseFirePA, to call on the General Assembly to "show the courage to pass commonsense reforms to reduce illegal gun trafficking to protect our police."

Indeed, continued inaction by lawmakers would be as callous as any gun trafficker's thoughtlessly delivering a potential murder weapon to the city streets.