Here's one method for understanding the passion and fear that gripped the House of Representatives as it debated the gun issue: Write columns in favor of gun control. Very soon, your mailbox is brimming with passionate letters from staunch opponents of any new gun regulations.

What you learn is that the National Rifle Association's power comes not just from the vast amounts of cash it spreads around the Capitol but also from an active constituency of gun owners who buy its arguments.

How else to explain the defeat in Friday morning's wee hours of Rep. Carolyn McCarthy's amendment that asked nothing more than a waiting period of three business days so background checks could be conducted on those who buy weapons at gun shows? "I'm only trying to stop the criminals from getting guns," the New York Democrat pleaded. But that minor inconvenience in the interest of saving lives was too much for the NRA, and for the House.

My pro-gun correspondents make clear that many in their ranks believe those who support modest gun regulations have a hidden agenda to deprive them of their weapons altogether. And many see gun control as the first step down the road to dictatorship.

A central theme in the letters is that there are plenty of gun laws already on the books -- 10,000 of them according to one reader, 20,000 according to another -- and they didn't prevent the tragedy at Columbine High School. Why would new laws be any more effective?

"Somebody, somewhere is breaking existing laws when kids use guns in anger," writes a reader from Syosset, N.Y.

"Just how many laws have to fail before gun control advocates even begin to question their beliefs?" asks a man from Bradenton, Fla.

The assumption here is that because existing gun laws aren't doing the job, we should give up on trying to fix them. But in virtually every other area where the laws weren't working -- from drunk driving to drugs to street crime -- the response has been to toughen the statutes, not weakened them. We were so concerned about drunk driving that we raised the drinking age to 21. Why is it so hard to raise the age for the purchase of guns?

"There is plenty of blame to go around in this case," a thoughtful reader from Large, Pa., says of the Columbine shootings, "but none of it belongs to honest gun owners."

Absolutely true -- and no one has said otherwise. In arguing for the three-day gun show waiting period, Rep. Fred Upton (R-Mich.) was right to insist that "legitimate gun owners have nothing to fear."

Moreover, if enforcement of gun laws is as faulty as the pro-gun side claims, isn't the smart course to keep weapons out of the hands of criminals in the first place? That's the point of McCarthy's waiting period. "A minor inconvenience for a handful," said Rep. Chet Edwards (D-Tex.), "is a very small price to pay for saving lives."

My correspondent also says this: "Gun control is not crime control; the key word is control. You can't control people until you take their guns away. Joseph Stalin, Adolf Hitler, Mao Tse-tung and Fidel Castro all knew this and acted on it."

Now, history shows that widespread ownership of guns is no guarantee against a dictatorship. Militias from opposing political parties were no obstacle to Hitler's seizure of power. Liberty thrives in other democracies that have far stricter gun laws than we do.

But to understand the ferocious opposition to even minor gun control measures, you have to know that my Pennsylvania correspondent expresses a fear that many in the pro-gun movement feel with all their hearts.

Instead of feeding the darkest fears of honest gun owners, you might hope politicians and gun organizations would dispel them. But these fears keep gun organizations in business and give a bloc of politicians an issue to talk about election after election.

I agree with all who wrote to say that gun laws alone do not explain the Columbine killings, and I appreciate the civility of many of my pro-gun correspondents. I just wish their leaders were serving them better. Surely most gun owners see the world as Rep. Edwards does. "I'm a hunter and a gun owner," he said. "But I'm also a father and a husband."

A three-day waiting period at a gun show is not aimed at law-abiding gun owners and is not the first step to dictatorship. Why is it so hard to agree on at least that?