LET'S HEAR IT for the Gross National Arsenal -- and to hell with the pleadings of thousands of America's top law enforcement officials and with the recommendation of a Reagan administration task force on crime. The U.S. Senate has voted to gut what minimal protections have existed against interstate and quickie sales of handguns. The senators swallowed the arm-America philosophy of the National Rifle -- make that read handgun -- Association. The result is a dangerous bill that deserves prompt and lasting burial in the House.

Why all this support for a legislative blessing of concealable weapons and for abetting what is already the worst record of any country in the world for annual handgun deaths? One big line of the gun lobby is that these attempts to maintain and approve minimal public safety protections -- such as a 14-day waiting period on handgun purchases -- are too much of a nuisance for dealers, sportsmen and others with legitimate interests in prompt transactions. But the proposals would have applied only to handguns and would have addressed other paper work concerns by lifting controls from rifles and other long guns.

Another excuse given for stripping away public safety protections is that criminals can always find handguns anyway. This neatly ignores efforts to stop quick sales to the mentally deranged impulse buyers and killers and to criminals in a hurry, who now won't even have to go to a black market -- any corner will do.

There is also an NRA favorite Hit-Myth that goes something like this: If you let the government do anything serious about monitoring the flow of handguns, then Uncle Sam will make a great big inventory of who's got anything around that fires. Dictators then can seize every weapon from under every rooftop and take over the country in no time flat. No fooling: some people actually seem to believe this.

The majority of Americans apparently don't buy this line. In response to polls over the years, they have supported more, not fewer, controls on handguns. Until similar reason reaches the Senate, law enforcement officials and the rest of us will have to hope that good sense prevails in the House.