WASHINGTON — “High Capacity Magazines … When ten rounds isn’t enough,” the Internet site offers.

When, exactly, would that be? Enough for what?

Jared Lee Loughner arrived at a Tucson Safeway on Saturday morning with a Glock 19 semiautomatic pistol outfitted with an oversized magazine that police say allowed him to get off 31 shots before he had to stop. The pause for reloading gave 61-year-old Patricia Maisch the chance to grab the new magazine from Loughner.

Guns don’t kill people, bullets kill people — and gunmen intent on killing a lot of people tend to think 10 rounds is not enough.

Maj. Nidal Hasan, the accused Fort Hood shooter, told a curious clerk at Guns Galore that he wanted the extended capacity clips because “he didn’t like spending time loading magazines when he was at the range,” according to court testimony. A few months later, Hasan, armed with 16 magazines and nearly 400 rounds of ammunition, allegedly killed 13 people.

For all the focus on weaponry, one of the most useful parts of the now-lapsed federal assault-weapons ban was that it prohibited the manufacture of magazines of more than 10 rounds. If the law, which expired in 2004, were still in effect, it would not stop crazed gunmen from inflicting damage, but it might limit the amount of damage they could inflict.

The modern politics of gun control do not favor those who back restrictions. Success, such as it is, consists of defending existing limits, not imposing new ones. Democrats were scared off from the issue after passing the assault-weapons ban and then losing control of Congress in 1994. Candidate Obama vowed to reinstate the assault weapons ban; President Obama, after a single year in office, had signed into law more repeals of federal gun-control policies than did President George W. Bush during his two full terms, according to the Brady Center to Prevent Gun Violence.

As a matter of political self-preservation, I would not advise Democrats to mount a full-scale push for new gun-control measures.

But with six dead in Tucson, including a federal judge and a 9-year-old girl, can we not as a society agree that these high-capacity magazines have no business in general commerce? New Jersey Democratic Sen. Frank Lautenberg and New York Democratic Rep. Carolyn McCarthy, whose husband was killed in the 1993 Long Island Rail Road shooting, plan to introduce legislation to reinstate the 10-round limit.

Glock, which manufactured the gun that Loughner used, doesn’t want to discuss the issue; the company did not return phone calls. The National Rifle Association is hiding behind protestations of respect for the victims. When I asked about the use of high-capacity magazines and proposals to limit them, NRA spokesman Andrew Arulanandam had only this to say: “At this time, anything other than prayers for the victims and their families would be inappropriate.”

At Gun Owners of America, which manages the astonishing feat of making the NRA look reasonable, John Velleco, the director of federal affairs, came up with two arguments against limiting magazines to 10 rounds. One, the classic slippery slope: First, they’ll take our 30-round magazines…..

“There is no OK number with Carolyn McCarthy and her allies in the Congress,” Velleco said. “They will only start with the number. … If the government can ban magazines with 10 or more rounds, it can ban a magazine that holds five or more rounds. There is no way to stop the arbitrariness of that sort of legislating.”

Two, the self-defense fallacy. “Who knows how many rounds a law-abiding person might need to protect themselves?” Velleco asked. “The lesson that a lot of Americans may take from this incident and others like it is that, as brave and quick as the police are, they can’t be everywhere all the time and maybe we need to take another look at our own self-protection.”

So a gun-carrying citizen is at the shooting, tries to stop Loughner, and 10 rounds isn’t enough? A high-capacity magazine in the hands of such a bystander would be more likely to inflict more damage on other innocent observers than to take down the shooter.

Members of Congress, Democrats and Republicans, safe districts and swing seats: Look at the pictures of Christina Green, shot dead at age nine. Imagine that she was your daughter, and she was hit by the 15th bullet, or the 25th.

And ask yourself: Isn’t 10 rounds more than enough?