The Star Tribune's June 21 editorial, "Gunrunning leaves a long trail of bodies," suggested that the cause of gun violence is drugs.

Sorry, but the cause of gun violence is guns. You can't mow down police officers with drugs, or even with bathtubs, knives or bottles. But you can make society much safer by adopting effective gun violence prevention laws and enforcing them.

The editorial states that in the case of one gunrunner, Paul Giovanni de la Rosa, the "system worked." The arrest was a success for the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). However, the fact that it took two years and an expensive investigation to stop a single gunrunner is a sign that our system is broken.

De la Rosa, while under investigation, continued funneling hundreds of guns to Mexico. If there had been a law limiting gun purchases to one a month, he could have been stopped much earlier. Those who claim criminals will always get guns overlook the fact that traffickers like De la Rosa reliably use the easiest method to get weapons -- the legal one.

But instead of closing down easy criminal access to guns, our elected officials have hogtied law enforcement, have suppressed information about the source of crime guns and have further weakened already inadequate gun laws.

The ATF is strapped for resources and operates under severe restrictions from Congress. As the New York Times reported last year, there are 200 ATF officers charged with policing all of the federally licensed gun dealers in the United States. (Minnesota alone has 1,800 such dealers.) Revoking the license of an irresponsible gun dealer is next to impossible under current law, and when the ATF tried to revoke a National Rifle Association board member's license, Congress pressured it to back off.

In a report a decade ago (available at www.endgunviolence.com), the ATF made several recommendations on improving gun laws to catch the bad guys. One was to close the "gun show loophole," the gap in the law that allows unlicensed sellers to sell guns to anyone they want at a gun show, no questions asked, no background check. Gun shows, the bureau said, were a "major trafficking channel." Since this report was issued, Congress has placed an Orwellian gag order on the ATF regarding the source of crime guns, and it has severely limited access to crime gun trace information, even by local police.

Congress allowed the assault-weapons ban to expire in 2005. Since then, people from Minneapolis to Mexico have been slaughtered with assault weapons. Big surprise. Most states also loosened background-check requirements for gun-carrying permits and have allowed the carrying of loaded guns in most public places. Crime rates were not reduced; gun injuries went up; self-defense cases never materialized, and permit holders committed police murders and mass shootings. Extremists have begun using loaded guns to intimidate elected officials at political meetings. If any other policies produced such disastrous results, they would have been reversed long ago.

New York City provides an example of how tough gun laws and enforcement can reduce crime. It has pursued gun trafficking aggressively and, as a result, has seen falling crime rates for two decades. New York is now safer than Minneapolis. Congress' response? Last year, it tried to impose loose gun laws on New York.

The situation is bad, but it can get worse. Just last month, the would-be Times Square bomber told a court that we are in a "war" and that there will be more attacks. We can hope that the attackers will be incompetent, because legal access to weapons is no problem for them.

Voters, including gun owners, need to demand change. It is time to call your senators and representatives to tell them to close the gun show loophole and the terror gap.

Heather Martens is executive director of Citizens for a Safer Minnesota and the Protect Minnesota campaign.