Ronald Reagan's go-ahead for the neutron bomb -- Soviet howls of protest notwithstanding -- has a silver lining for the kremlin. First of all, the decision is a windfall for Soviet propagandists -- a gift-wrapped lever for their bid to encourage West European uneasiness over Mr. Reagan.
Much more importantly, the neutron bomb move could help Moscow solve a basic policy problem: What (besides angry Pravda commentaries and a seemingly endless string of "peace initiatives") to hurl back at this "anti- Soviet" US President.
Initial Soviet coverage of the US neutron bomb decision, including a commentary carried by Pravda Aug. 10, hinted at one possible answer: The Kremlin could produce neutron weapons of its own. The implied message would be clear: "We can answer you, Mr. Reagan, in more than words."
Whether the Soviets follow through on this hint (President Leonid Brezhnev said back in 1977 he would match any US move to produce neutron weapons) may afford the most important practical test to date of Kremlin strategy toward the Reagan administration.
Mr. Brezhnev was quoted as telling a group of visiting US senators here in 1978 that Moscow had already tested a neutron weapon -- a statement echoed by the French defense minister Aug. 10 after the US decision on the warhead -- but had "never started production."
Even before the US decision, there seemed signs of uncertainty here over just how to handle Mr. Reagan -- whether to "wait him out" in hopes of gradually improved relations, or to adopt a gradually more muscular approach.
So far, the choice has been to wait, presumably with an eye toward planned talks in September with US Secretary of State Alexander M. Haig Jr. and resumed discussions on missile forces in Europe shortly thereafter.
Six months of Ronald Reagan, Soviet officials argue, have produced US rearmament, a bid for a heightened US military profile in the Mideast, an arms deal with Pakistan, and at least prospective arms sales to China.
The Soviet response has consisted, mostly, of barbed words, nonstarting peace plans for most of the world, and an agreement Aug. 15 to buy a further batch of US grain.
Many foreign analysts here have been assuming there is not much else the Soviets can riskm doing. The Soviet leadership, the argument goes, is old and getting older. The domestic economy is troubled and getting more so.
A markedly tougher line toward Washington could worsen relations with West Europe, too, further strain the Soviet economy, and threaten the political position of a Soviet President who has invested personally in the idea of detente.
Conversations with senior officials, meanwhile, suggest an opposite view: that the key economic element in detente, trade with West Europe, is secure, and that the Kremlin has so far consciously opted to treat Mr. Reagan with "political wisdom, maturity,. . . and restraint."
Whichever the case may be, there have been scattered hints in the past month of an incrementally toughened Soviet attitude toward Mr. Reagan.
On Aug. 8, for instance, Soviet Foreign Minister Andrei Gromyko seemed to go beyond traditional warnings that Moscow could "not remain indifferent" to US arms policy toward nearby China and Pakistan.
Writing in the authoritative newspaper Pravda, he reminded readers, US diplomats here no doubt among them, that Moscow supplies weaponry to India, a state that borders the USSR, Pakistan, and China.
He added, in what seemed a reference transcending the Soviet-Indian relationship, that "no one should have any doubts on the capacity of the Soviet state to defend itself and its allies and friends."
All this remains, of course, only words. But since July the Soviets have also begun what might be called a battle of military maneuvers with the US and its allies.
While denouncing relevant exercises by the West and Japan, the Soviets have:
* Announced a series of missile-launch tests in the Pacific.
* Staged joint naval exercises with Syria, amid heightened Mideast tension.
* Begun, in recent days, uncommonly large exercise in the Baltic sea.
Asked to explain the timing of the Soviet- Syrian exercise, a Soviet official riposted: "Why are there joint maneuvers . . . in every corner of the globe by the US?"
Another official said the Syrian maneuver, and a more recent ceremonial call in Libya by Soviet warships, should "serve as a reminder of Soviet presence" in the Mideast, a "region mush closer to the Soviet Union" than to the US.
The Baltic exercise could be linked to the resurging crisis in nearby Poland. They could also conceivably relate to announced Western-South American exercises in the North Atlantic, amply and acridly criticized here.