What good are laws that are not enforced?

Local, state and federal advocates of more limits on firearms ownership and use might do well to take aim at another method of curbing the mayhem caused by gun violence — enforcing existing laws.

Just over a week ago, five people were killed and six others wounded when Gary Martin pulled out a gun and started shooting, right after he had been told he was being fired from his job at an Aurora, Ill., manufacturing plant.

Martin, 45, was killed in a shootout with police.

It turned out Martin used a gun that should have been taken away from him years ago.

Martin bought his gun, a .40-caliber pistol, in 2014.

A background check was conducted before he was allowed to take the firearm home.

But a few months later, a second background check disclosed something the initial one missed: Martin’s 1995 conviction for stabbing an ex-girlfriend in Mississippi.

Under Illinois law, that disqualified Martin from having a gun permit and owning a firearm. Police dutifully sent him a letter informing Martin of that and ordering him to turn his pistol over to the authorities.

Then, everyone forgot about Martin — until last week, when he used the gun he wasn’t supposed to have to create a bloodbath.

Had Illinois authorities done their jobs, Martin’s victims might well be alive today.

It happens with distressing regularity: A deranged person slaughters innocent victims. Gun control advocates call for new limits on firearms. Then, it is disclosed it was not lack of enough laws but, rather, failure to enforce those already on the books that resulted in the tragedy.

This is not an argument against consideration of new limits, such as those intended to keep guns out of the hands of the mentally unbalanced.

But it is a suggestion that more attention needs to be given to compliance with existing regulations.

What good are gun safety laws — those in effect now or those being proposed — if enforcing them is not a priority?