Congress denied President Reagan's repeated requests in his first term to produce new chemical weapons, and now he is back with the same request. The tone this year, however, is subdued. The president says his chemical warfare (CW) program has a "high" priority. As these things go, "high" is not very high. The indication is that the administration will give it the old college try but will save its heaviest artillery for other causes.

The fact is that the case for breaking President Nixon's now 16-year-old moratorium on production of CW weapons is no better than it's ever been. The basic argument is that to deter the Soviets' use of their considerable stores of CW weapons, the Americans must have a credible capability to retaliate in kind. The familiar and still-good response is that deterrence can be maintained by other means: by the old stuff still in the American CW stockpile or, if the Pentagon is right that the stockpile has deteriorated, by anti-CW measures and by threats to use other types of weapons.

Resuming production of CW weapons, moreover, would convulse Europe, the principal place where the United States might plan to conduct a CW defense. The Pentagon has lots of fancy arguments about bolstering deterrence and raising the nuclear threshold, and all of them ignore the central political reality that a new CW program would drive up the wall the people in whose behalf the program is chiefly justified. Surely it is not necessary to point out that, with the nuclear and space talks about to resume, this is a peculiar moment for the United States to hand Moscow a powerful new propaganda club to wield among the allies.

After all, a powerful old propaganda club already exists. Fortunately, it is in American hands. The Kremlin's continued production of CW weapons and its alleged sponsorship of chemical warfare against local peoples in Indochina and Afghanistan enables and requires the United States to portray the Soviet Union as the planner and perpetrator of a dread outlawed form of warfare.

Just the other day Pravda again indulged the Soviet practice of seeking to deflect world attention from its own CW policies by accusing the administration of "preparing for a chemical rearmament of America." Let Mr. Reagan back off his CW proposals, which are unlikely to go far anyway, and keep the heat on where it belongs: on Moscow. Campaigning for a new CW program amounts to throwing away an ace.