The gun control controversy is only the latest of many issues to be debated almost solely in terms of fixed preconceptions, with little or no examination of hard facts.

Media discussions of gun control are dominated by two factors: the National Rifle Association and the Second Amendment. But the over-riding factual question is whether gun control laws actually reduce gun crimes in general or murder rates in particular.

If, as gun control advocates claim, gun control laws really do control guns and save lives, there is nothing to prevent repealing the Second Amendment, any more than there was anything to prevent repealing the Eighteenth Amendment that created Prohibition.

But, if the hard facts show that gun control laws do not actually control guns, but instead lead to more armed robberies and higher murder rates after law-abiding citizens are disarmed, then gun control laws would be a bad idea, even if there were no Second Amendment and no National Rifle Association.

The central issue boils down to the question: What are the facts? Yet there are many zealots who seem utterly unconcerned about facts or about their own lack of knowledge of facts.

There are people who have never fired a shot in their life who do not hesitate to declare how many bullets should be the limit to put into a firearm's clip or magazine. Some say ten bullets but New York state's recent gun control law specifies seven.

Virtually all gun control advocates say that 30 bullets in a magazine is far too many for self-defense or hunting -- even if they have never gone hunting and never had to defend themselves with a gun. This uninformed and self-righteous dogmatism is what makes the gun control debate so futile and so polarizing.

Anyone who faces three home invaders, jeopardizing himself or his family, might find 30 bullets barely adequate. After all, not every bullet hits, even at close range, and not every hit incapacitates. You can get killed by a wounded man.

These plain life-and-death realities have been ignored for years by people who go ballistic when they hear about how many shots were fired by the police in some encounter with a criminal.

As someone who once taught pistol shooting in the Marine Corps, I am not the least bit surprised by the number of shots fired. I have seen people miss a stationary target at close range, even in the safety and calm of a pistol range.

We cannot expect everybody to know that. But we can expect them to know that they don't know -- and to stop spouting off about life-and-death issues when they don't have the facts.

The central question as to whether gun control laws save lives or cost lives has generated many factual studies over the years. But these studies have been like the proverbial tree that falls in an empty forest, and has been heard by no one -- certainly not by zealots who have made up their minds and don't want to be confused by the facts.

Most factual studies show no reduction in gun crimes, including murder, under gun control laws. A significant number of studies show higher rates of murder and other gun crimes under gun control laws.

How can this be? It seems obvious to some gun control zealots that, if no one had guns, there would be fewer armed robberies and fewer people shot to death.

But nothing is easier than to disarm peaceful, law-abiding people. And nothing is harder than to disarm people who are neither -- especially in a country with hundreds of millions of guns already out there, that are not going to rust away for centuries.

When it was legal to buy a shotgun in London in the middle of the 20th century, there were very few armed robberies there. But, after British gun control zealots managed over the years to disarm virtually the entire law-abiding population, armed robberies became literally a hundred times more common. And murder rates rose.

One can cherry-pick the factual studies, or cite some studies that have subsequently been discredited, but the great bulk of the studies show that gun control laws do not in fact control guns. On net balance, they do not save lives but cost lives.

Gun control laws allow some people to vent their emotions, politicians to grandstand and self-righteous people to "make a statement" -- but all at the cost of other people's lives.