This is one anniversary they are not going to celebrate in the Kremlin. On Feb. 18 it will be six months since Yuri Andropov's last public appearance. The Soviets are tight-lipped about the situation of the general secretary. Westerners can only speculate on the whereabouts of Mr. Andropov.
If you believe news dispatches from Moscow based on tips from allegedly well-informed Russian sources, there is little reason to get excited. The Soviet leader is absent for ''temporary reasons'' but still very much in charge. Andropov issues major policy statements and gives interviews to Pravda. His economic program was adopted at the December 1983 Communist Party Central Committee Plenum. And his proteges are promoted to the ruling Politburo. His trusted aides visit him at a secluded dacha or get instructions from him by telephone. Andropov's absence notwithstanding, the USSR should not be considered leaderless.
Not quite that simple. Andropov has scored in becoming the first ghost selected as Time magazine's ''man of the year,'' but it is doubtful he has been as successful in consolidating his power in the USSR and is in control.
Statements and interviews attributed to him could have been prepared by assistants and approved by the Politburo. There is information indicating that the general secretary has made some contribution to these documents. Alexander Bovin, an Izvestia columnist who is reported to moonlight as Andropov's speech writer, told the Washington Post that he had a 10-minute phone conversation with the Soviet leader on Dec. 20, about the time Andropov would be expected to review drafts of the report delivered in his name at the December plenum.
But the Bovin story hardly proves that Andropov was in a position to offer real guidance. No new economic reforms were endorsed at the plenum. All the Central Committee has done is to repeat the decision to proceed with modest and contradictory economic management experiments approved by a previous plenum.
Andropov's alleged conciliatory interview with Pravda was actually as harsh as Foreign Minister Andrei Gromyko's anti-Reagan speech in Stockholm. The fact that some American reporters found seeds of reconciliation in this new attack on the US administration tells more about their imagination than the mood of the Soviet leadership. Nothing gives reason to believe that Andropov opted to overrule Gromyko.
As far as reconstructing the Politburo is concerned, the general secretary's success is also uncertain. Only one member has been ousted since Andropov came to power - Andrei Kirilenko, an enemy of Andropov's rival Konstantin Chernenko. But Kirilenko's departure was determined even before Leonid Brezhnev's death.
Additions to the Politburo do not necessarily signify a strengthening of the Soviet leader's base. Neither of the two newly elected members - Vitaly Vorotnikov and Mikhail Solomentsev - elected at the December plenum, has a record of association with Andropov. A newly elected candidate (nonvoting) member, Victor Chebrikov, could probably be counted among the general secretary's loyalists. But his election was predictable. As the head of the KGB, Mr. Chebrikov was ex-officio entitled to a seat in the Politburo. Candidate membership was perhaps the least that could be offered short of insult.
Significantly, Andropov's former competitor Chernenko is running high. In reports on nominations to the Soviet rubber-stamp Supreme Soviet, his name was listed out of alphabetical order immediately after those of Andropov and Prime Minister Nikolai Tikhonov. Chernenko's name was mentioned ahead of other Politburo members under several obituaries of Soviet officials. And the Soviet press has widely reported the publication of the second edition of Chernenko's speeches.
Andropov's position, however - assuming his health does not deteriorate further - appears secure. As a rival, Chernenko is too old and without sufficient respect to present a formidable challenge. There may be a Politburo consensus that a physically handicapped Andropov is preferable to the uncertainties of succession.
Still, Andropov is currently incapable of providing an effective leadership. Joseph Stalin's lieutenants were summoned to the dictator's secluded dacha and given orders nobody dared disobey. Andropov does not enjoy similar authority. Today key decisions are made collectively at Politburo meetings. As long as he cannot attend them he is handicapped politically. Also, in the Soviet bureaucracy only an aggressive and dynamic leader is capable of forcing functionaries to amend their ways to start working in earnest.
Since Brezhnev's death there is more emphasis on discipline, political orthodoxy, and law and order. Yet the present ''no nonsense'' muddling-through, while different from the relaxed muddling-through before Andropov, hardly amounts to effective governing. Despite the Soviet regime's slippage both at home and abroad, no difficult controversial decisions are being made in Moscow.
This is good news for Ronald Reagan. Andropov's illness has let the administration off the hook as far as relations with the Soviet Union are concerned. Washington can claim it is ready to deal, but there is nobody to have a serious dialogue with. The Soviet leadership, rather than Reagan's policies, is blamed for the stalemate in superpower relations during the election year.
The point is well taken, but it does not tell the whole story. The leaderless Soviet Union may be a poor partner in cooperating to break the current deadlock. Yet, was the deadlock inevitable to start with, and what - if any - is the administration's responsibility for it? That is the issue for debate during the 1984 campaign.