Unfortunately, the beliefs are just so strongly held that some prominent hosts of news programs, such as Morgan, refuse to accept facts, and go so far as to conjure up their own numbers when reality isn't to their liking. All this makes for a pretty confusing show, with viewers hearing one side say murders rose and another saying that they fell.
Take one of my five debates on CNN after the Newtown attack. This particular discussion, involving Piers Morgan and Christiane Amanpour, was not unusual.
Lott: "Every place that guns have been banned, murder rates have gone up. You cannot point to one place, whether it's Chicago or whether it's D.C., or whether it's been England or whether it's been Jamaica or Ireland."
Morgan: "I'm sorry, but that's just a complete lie. It's a complete lie. The gun murder rate in Britain is 35 a year, average. You need to stop repeating a blatant lie about what happens in other countries. ... No, you're not going to get away with this. You lied about it the other day. ... Stop lying, because what you say drives Americans to defend themselves."
Gun-control advocates like to argue that the United States has a higher murder rate than other countries, such as the United Kingdom, because it has a higher gun ownership rate. But that is simplistic. Countries have different murder rates for many different reasons, and my point was that Britain's murder rate rose after the ban, just as it has in other countries. Unwilling to let me explain the point, Morgan turned to Amanpour.
Amanpour: "After [a school massacre in] Dunblane, they put in these bans, they put in these punishments, fines, jail sentences, etc., and it's true that straight afterward there wasn't a huge change, but 2002, 2003 until 2011 the rate plummeted by 44 percent."
So what really happened in Britain? What Amanpour conveniently failed to mention was that the handgun ban went into effect on Jan. 1, 1997. After that, the rate of murders went up sharply for seven years.
It is true that the homicide rate fell after 2003, but that was clearly following a dramatic increase after the ban. Indeed, 15 years after the ban, the homicide rate was still slightly higher than it was before the ban in 1996. For 14 of the 15 years after the ban, the murder rate was higher than it was in 1996.
Nor is it clear that the drop after 2002 and 2003 can be attributed to the handgun ban. More likely it was the effect of a large, 13 percent increase in the number of police who started in 2002.
Gun-control advocates - be it in the United Kingdom or the United States - often consider only gun murders, not murders generally. If you disarm law-abiding people, non-gun murders might rise simply because victims aren't able to defend themselves as well. But what some people might find surprising is that firearm murders also rose after the ban. Indeed, there have been only two years after the ban in which the number of firearm murders was below what it was in 1996.
The pattern is the same elsewhere. Here in America, we have seen firsthand the same increases in murders after Washington and Chicago banned handguns in 1977 and 1982, respectively. And in such island nations as Ireland and Jamaica, murders and violent crime soared dramatically.
Not only is there a huge number of guns in circulation already around the world, but they are all too easy to smuggle into even island nations. Just as governments are powerless to stop illegal drugs from entering a country, they find it very difficult to stop illegal guns.
Gun-control advocates take a very naive view of our ability to restrict guns. Unfortunately, when law-abiding citizens, not criminals, primarily obey gun bans, it is easier for criminals to commit crime. But at some point the constant increases in murder rates after bans must shake the faith of even the most diehard gun-control advocates.
John R. Lott Jr. is a former chief economist at the U.S. Sentencing Commission and the author of the expanded third edition of "More Guns, Less Crime" (University of Chicago Press, 2010).