TALK ABOUT BUCKING the tide--and bringing back the worst old days of quick-and- dirty interstate handgun traffic throughout the country--that's the serious threat to law enforcement contained in a gun-decontrol bill scheduled for action this week in the Senate Judiciary Committee. Committee members of both parties share the concerns of federal, state and local law enforcement authorities that enactment of this measure would seriously hamper crime-fighting efforts nationwide, and anyone else the least bit alarmed by the existing proliferation of concealable firearms should be calling for this bill to be deep-sixed.

The bill was first introduced last year by Sen. James A. McClure (R-Idaho) and Rep. Harold L. Volkmer (D-Mo.) as a way of creating serious loopholes in the the few federal controls that were enacted in 1968 after the murders of the Dr. King Jr. and Robert Kennedy. The purpose of the earlier law was to make it harder for nonresidents of a state or felons, fugitives, drug addicts or court-adjudged mentally defective people to buy handguns.

But the McClure-Volkmer proposal would even rip up these minimal restrictions on interstate handgun traffic--and even vitiate state and local rights to eliminate such sales. As if this weren't dangerous enough, now comes an additional provision proposed by Sen. Orrin G. Hatch (R-Utah): not only would it eliminate almost any safeguards against indiscriminate state-to-state handgun sales, but it also would destroy existing minimal record- keeping and tracing procedures used in solving crimes.

What about any required waiting period for would-be buyers of deadly handguns, one of the key recommendations of Attorney General William French Smith's Task Force on Violent Crime? Forget it under this formula, along with most of the other recommendations to strengthen tracing procedures, record handgun losses and thefts, and ban the importation of unassembled gun parts that are the makings of "snubbies"-- the short handguns used in most violent crimes.

The issue here has nothing to do with sportsmen, gun clubs, law-abiding collectors or owners of firearms. Long guns, in fact, are not the concern at all--something the National Rifle-Make-It-Handgun Association doesn't seem to care about these days, even if hunters and other solid citizens may wonder why the NRA lumps them in with every handgun buyer, brandisher, bandit or hit man in America.

Tough and sure sentencing is one step in the fight against crime--and members of both parties in Congress as well in the executive branch of this administration would add to it a waiting period for sales, criminal records checks, closing of the imported-parts loophole and prompt reporting of gun thefts. These are the key features of a crime-control/handgun-control measure--the Kennedy-Rodino bill that has widespread bipartisan support. It would do something about handgun violence instead of undoing, which is the effect being sought through the McClure- Volkmer-Hatch bills.

That is why members of the Senate Judiciary Committee, who sense the growing popular demand--law-abiding gun-owners included--for safer streets and homes and who support serious crime controls, should respond effectively this week by rejecting the McClure-Volkmer-Hatch-handguns-galore bills and turning attention to a sensible national campaign against the insanity of unchecked handgun violence.