Updated

In the wake of the Colorado tragedy, Democrats in Congress have wasted no time introducing new gun control legislation. Today, Sen. Frank Lautenberg and Rep. Carolyn McCarthy introduced a bill that bans the sale of ammunition online and by mail.

Last Thursday, six Senate Democrats proposed amending the cybersecurity bill to ban magazines holding more than 10 bullets. President Obama also promoted renewing the Assault Weapon Ban, announcing, “AK-47s belong in the hands of soldiers, not on the streets of our cities.”

The reaction is understandable, but despite the best of intentions, the laws won’t stop these attacks from occurring.

Take the Lautenberg and McCarthy proposed ban on online ammunition sales. The proposal would make rules for buying ammunition the same as for buying a gun. But the Colorado killer was able to legally buy a gun from a dealer and, under the proposal, he still would have been able to buy the ammunition. The requirement of a photo ID seems equally irrelevant in this case.

The law also would mandate licensed ammunition dealers to report the sale of more than 1,000 rounds of ammunition to an unlicensed person within any five consecutive business days. But what good would that do? The Colorado killer apparently planned his attack at least four months in advance. If he were trying to hide his ammunition purchases, he could easily have spread them out over time.

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What the ban would do is raise the cost of buying ammunition. But does anyone really believe that even a 20 or 30 percent increase in the price of ammo would be the difference that stopped someone intent on committing suicide or spending the rest of their lives in jail from buying ammo? It isn’t like these guys have to worry about making payments on past due credit card bills.

We have already tried the magazine ban and it won’t be any more helpful now than it was when the Federal Assault Weapon Ban was in effect from 1994 to 2004. A magazine, which is basically a metal box with a spring, is trivially easy to make and virtually impossible to stop criminals from obtaining.

Further, the guns in several recent mass shootings (including the one in Aurora and last year in Tucson) have jammed because of the large magazines that were used. The reason is simple physics. Large magazines require very strong springs, but the springs cannot be too strong, or it becomes impossible to load the magazines. Over time, the springs wear out, and when a spring loses its ability to push bullets into the chamber properly, the gun jams. With large springs, even a small amount of fatigue can cause jams.

President Obama’s discussion of AK-47s is no more helpful, but given his long involvement in the gun control debate he surely must know what he was saying was incorrect. The civilian version of the AK-47 is not the machine gun used by militaries around the world. The civilian version merely looks like the military version on the outside, but its inside guns are the same as a deer-hunting rifle. The civilian version uses essentially the same sorts of bullets as deer-hunting rifles, fires at the same rapidity (one bullet per pull of the trigger) and does the same damage.

If Obama wants to campaign against semi-automatic guns based on their function, he should go after all semi-automatic guns. After all, in 1998, as an Illinois state senator, he supported just such a ban -– a ban that would eliminate most of the guns in the United States.

But no published peer-reviewed studies by economists or criminologists find the original federal or state assault-weapons ban reduced murder or overall violent crime.

Since the federal ban expired in September 2004, murder and overall violent-crime rates have actually fallen. In 2003, the last full year before the law expired, the U.S. murder rate was 5.7 per 100,000 people. Initial data for 2011 shows that the murder rate has fallen to 4.7 per 100,000 people.

The big problem with gun control is that it is the law-abiding good citizens, and not those intent on committing the tragedies like those in Colorado, who obey these laws.  It is hard not to notice, but very aggressive gun control hasn’t prevented multiple-victim public shootings in Europe.

In last year’s shooting near Oslo, 69 people were killed and an additional 110 injured. Germany, a country with some of the strictest gun control in the world — it requires not only extensive psychological screening but also a year’s wait to get a gun — has been the site of three of the worst five multiple-victim K-12 public school shootings in the world, all in the past decade. There are more examples of attacks in countries with strict gun control, like in Austria, Britain, France, Finland and Italy.

The guns used for the attacks in Germany and Norway were obtained illegally. When individuals plan these attacks months or even years in advance, it is virtually impossible to stop them from getting whatever weapons they want.

If we finally want to deal seriously with multiple-victim public shootings, it is about time that we acknowledge a common feature of these attacks: With just a single exception, the attack in Tucson last year, every public shooting in the U.S. in which more than three people have been killed since at least 1950 has occurred in a place where citizens are not allowed to carry their own firearms. The Cinemark movie theater in Aurora, like others run by the chain around the country, displayed warning signs that it was prohibited to carry guns into the theater.

All the public mass shootings in Europe fit this rule. Take Switzerland, which has very liberal concealed carry laws.

The country also has had several big public mass shootings over the last decade, but there again all of their attacks have taken place in the few areas where guns are banned.

Last week, President Obama promised that gun control was going to be an important topic in the presidential campaign. The issue was really always there, even if it wasn't being openly debated. Whoever wins the presidency will likely determine who controls the Supreme Court and the fate of gun control laws.

Bans, like the gun-free zones, can be counterproductive.  Hopefully, the debate will finally acknowledge that well- intended laws are not enough.