The cold-blooded killing of Philadelphia Police Sgt. Stephen Liczbinski is yet another sad reminder of the violence that rages on the streets, thanks to the easy access of guns and a disregard for human life.

Sgt. Liczbinski should be celebrating his 40th birthday today with his wife and three children. Instead, his family is preparing for his funeral.

Sgt. Liczbinski was gunned down Saturday while trying to stop a band of thugs fleeing from a harebrained bank robbery in Port Richmond. As he lay dying in the street, the 12-year police veteran from the Northeast reportedly said: "Tell my wife I'll miss her."

The city of Philadelphia can't afford to lose police officers like Sgt. Liczbinski - described as a cop's cop. He is the third Philadelphia officer shot and killed in the line of duty in the last two years. Our hearts go out to his family.

Sgt. Liczbinski's death should motivate state lawmakers to stop kowtowing to the gun lobby and pass meaningful gun-control laws, including a ban on assault weapons such as the one used to kill Sgt. Liczbinski.

Mayor Nutter said yesterday that the National Rifle Association owed Sgt. Liczbinski's family an apology. The mayor recently signed five local gun measures into law, including one that would outlaw the possession and sale of certain assault weapons. But the NRA sued and obtained a temporary restraining order halting enforcement of the new measures.

Nutter is just trying to do what state lawmakers don't have the brains or backbone to do.

There is no legitimate reason that military-style assault weapons used to kill people should be sold to the public.

In 1994, Congress banned the sale of certain assault weapons, such as AK-47s, Uzis and TEC-9s. But the ban expired in 2004.

Studies differ as to whether the ban had any impact. But other states have banned assault weapons, including New Jersey and New York. Pennsylvania lawmakers should do the same if they are serious about protecting citizens and police officers.

U.S. Rep. Carolyn McCarthy (D., N.Y.) introduced a bill last year to reinstitute the federal assault-weapons ban. Among the presidential candidates, Sens. Hillary Clinton and Barack Obama support extending the ban, while Sen. John McCain voted against the measure in 1994 and remains opposed to it.

How many more people have to die before lawmakers and gun advocates will accept reasonable gun laws that help reduce the senseless violence?