TIME NOW for Round Four Million in the cross fire of debate over gun controls and whether the District of Columbia's tough law has helped curb handgun-related crime. Clearly something has -- and that is what the latest argument is all about. The U.S. Conference of Mayors has released a study showing that handgun-related crime in the District has decreased significantly in the last three years and goes on to conclude that this is largely because of the city's law, which happens to have been in effect during this same period.

Not so fast, say officials of the police department, who suggest understandably that maybe improved law enforcement efforts had a little something to do with the drop. Maybe too, the officials note, the decline was connected with cyclical reductions in over all crimes. Fair enough -- the police surely deserve credit; and as for those cycles, in 1979 and on into this year, all crime -- including gun-related cases -- has started increasing.

As you might expect, the National Rifle Association doesn't buy the report's argument either.On cue and off base once again, NRA officials have taken their predictable potshots at the law, based largely on their tired arugment that the bad guys will get guns no matter what, so why have any controls on handgun traffic. But why not? Is anyone really hurt by this law? A chief factor in every gun crime surely is a gun. So isn't it possible that far more people may be a little better off if the gun market is officially closed here?

Yes, criminals can get guns and no, they are not generally the first folks in line to register weapons. But guess where most of the weapons used in Washington-area crimes come from? The largest source is Virginia and No. 2 is -- that's right -- Maryland. So what might happen if these two states cracked down? Better yet, what if there were national controls on handgun traffic? Wouldn't it be just a little bit harder for criminals to get their hands on guns?

Besides, even if the conclusion of the Conference of Mayors report is too sweeping, it isn't just the criminals' guns that are dangerous. We still believe that even a local handgun ban may be reducing the possibility of accidents in homes. That in itself is ample justification for the District's law -- and for similar protections throughout this region.