The guns were sold in Virginia, the lives taken violently just a few miles away. It is the guns bought there and used for crimes elsewhere that have long had mayors around the United States angry.

With a credit card and a lie, Cho Seung-Hui was able to walk out of a pawnshop and a gun store with the handguns he later used to slaughter 32, and then kill himself. The state's background check failed to turn up his history of mental illness in each of the two sales.

Other guns sold in Virginia have surfaced in significant numbers of crimes in New York and throughout the Northeast corridor - Washington, Philadelphia, New York - inspiring Mayor Michael Bloomberg to become a crusader against gun trafficking.

Virginia is a key source for illegal guns along the East Coast, as well as a target of gun control activists for lax enforcement of its laws, though they are not the nation's loosest. Bloomberg has taken on the issue and built a coalition with more than 200 mayors.

"What happened in Blacksburg was a terrible tragedy - 32 people were murdered. But if you take a look, 30 people are murdered every single day in America, it is just spread across 50 states, so it isn't a newsworthy event," Bloomberg said two days after the shooting, when more city leaders joined Mayors Against Illegal Guns.

"The Blacksburg tragedy is taking place every single day," Bloomberg said.

The FBI found that 41 people, on average, died in homicides every day in 2005; 28 were slain with guns.

Stopping the flow of guns will be an uphill fight for the mayors. Neither side in the gun control debate is shifting its position following the Virginia Tech shootings and Virginia Governor Tim Kaine declared he had nothing but "loathing" for those who would make the tragedy a "political hobby horse to ride".

Still, the statistics put Virginia squarely in the midst of the argument. Data once collected by the Bureau of Alcohol, Tobacco and Firearms (ATF) tracked the source of guns used in crimes that were collected by city police across the country.

In New York, four out of five guns came from out of state. The single largest source of those out-of-state guns? Virginia (with Florida, North Carolina and Georgia right behind).

The statistics run up the East Coast. In the District of Columbia, Maryland and Virginia together supplied more than half the guns found. In Camden, New Jersey, a poor city over the Delaware River from Philadelphia, Virginia was the source of one out of six guns. Virginia was the biggest out-of-state source in Philadelphia and Baltimore.

Each region of the country has its own sources of guns. Chicago drew many from nearby Indiana, but also from the deep South; most Miami guns came from Florida, but its out-of-state sources were Georgia, Texas and California.

"They're going from low-regulation places towards high-regulation places," said Daniel Webster, co-director of the Johns Hopkins Center for Gun Policy and Research, who last year produced a national analysis of state regulation of firearm dealers.

It's simple supply and demand - guns are easier and cheaper to get with fewer regulations, so a network springs up in response to the demand for guns in cities where they are harder to get.

Virginia's gun laws are far from the worst, though they are much less restrictive than states such as New York or New Jersey.

The Brady Center to Prevent Gun Violence ranks Virginia in the middle-third of the country, chastising it for a loophole that allows sales without background checks at gun shows, but applauding it for a bar on bulk purchases that limits buyers to one handgun a month. Only Maryland and California have a similar law.

And the argument that gun rights advocates often bring up that fewer crimes would take place if existing laws were simply enforced cannot be ignored in the Virginia Tech tragedy.

The regulations broke down because Cho's name was never sent to either state or federal databases as a prohibited buyer, despite a 2005 ruling by a special justice that found that his mental illness made him a danger to himself.

That ruling should have prohibited him from buying a gun anywhere in the country, according to federal rules that followed a 1968 law, according to the Brady Center. Cho filled out the required forms for each of the guns he bought, a Walther .22-caliber bought over the Web for US$268 (€197) from a Wisconsin dealer and picked up in February at a pawn shop in Blacksburg, and a Glock 19 that he purchased in March at a Roanoke gun shop, with ammunition, for US$571 (€420). To get the guns, Cho had to say whether he had ever been found "mentally defective".

Another failure in the system is behind the illegal gun trade targeted by Bloomberg and his fellow mayors. New York Police Department investigators say it works like this: Unable to buy handguns at home, street criminals simply look elsewhere. Of the 7,758 illegally owned firearms recovered by the NYPD between 2004 and 2005, 90 percent originated at out-of-state gun shops.

Some of those weapons were purchased legally by law-abiding citizens, then stolen, but police say a larger number were bought by black-market dealers themselves with the help of middlemen called "straw purchasers."

The traffickers pay friends and acquaintances with clean criminal records to buy weapons at sporting goods stores and pawn shops in the states where they live. The buyers then give the weapons to the traffickers, who smuggle them to their home cities and sell them on the street at many times the original price.

That is the issue at the center of the mayors' campaign, which aims to crack down on dealers who knowingly sell to straw purchasers.

But the politics of gun control has left the national discussion dormant.

The Columbine tragedy of April 20, 1999, whose teenage killers Cho mentioned in his delusional ramblings, did not lead to sweeping restrictions.

Instead, political strategists widely concluded that Democrat Al Gore's support for tougher laws lost him critical votes in his razor-thin loss to George W. Bush in 2000.

And now, letters-to-the-editor and websites, while rife with dismay over the glorification of and easy access to guns in our country, also feature the counter-argument that if guns had been allowed on campus, someone with a weapon may have been able to stop the killing.

Mayors say the political inaction has left their cities vulnerable.

Gun politics has blocked city officials from using the gun tracing data collected by the ATF - the latest available is from 2000. Bloomberg's group has launched a campaign to pressure Congress to change the law and make current data available, while New York City has sued more than two dozen gun dealers, including several in Virginia, for selling weapons illegally.

"The fact is, crime is on the rise throughout our nation, and murder rates are going up in far too many towns," Bloomberg said. "This tragedy... is a terrible reminder of what can happen when guns wind up in the wrong hands."

(China Daily via agencies April 23, 2007)