MOSCOW — THE annual celebration of the Bolshevik Revolution used to be as unshakable a symbol of Soviet power as the innumerable statues of the revolution's leader which glower over virtually every public square. With unchanging ritual, the gray old men of the Communist Party leadership stood atop Vladimir Lenin's mausoleum in Red Square as the might of the Soviet Red Army paraded past. Kremlinologists studied the order in which the men stood for their annual clue to the pecking order among this secretive group. Western military attach'es occupied themselves with getting a rare glimpse of the latest piece of Soviet military hardware.
In these days of open political struggle, those concerns seem quaintly dated. Political observers will watch today to see if Russian populist leader Boris Yeltsin takes his place on the stage with his rival, Soviet President Mikhail Gorbachev. And the predicted first-time appearance of a Soviet SS-25 mobile nuclear missile is unlikely to send attach'es rushing to send cables home.
The focus of attention this Revolution Day is on the controversy surrounding it. As elections topple the Communist Party from power in republic after republic, even in the Soviet capital itself the legitimacy of the anniversary is under assault. Wherever it has gained power, the opposition is challenging the Great October Revolution of 1917, seeking to remove its symbols - from the statues of Lenin to the Nov. 7 parade itself.
In the Baltic republics of Latvia, Estonia, and Lithuania, the nationalist governments have publicly denied permission for the parades and declared Nov. 7 to be an ordinary working day. In Georgia, where the nationalists just swept to victory in republican elections, the Army took the hint and moved its parade from the capital's main thoroughfare to a garrison drill ground.
In the Ukraine, the nationalist democrats oppose any celebration of what they call ``a day of mourning'' and plan to hold a demonstration to block the parade.
The radical mayors of Leningrad and Moscow have called on citizens not to participate in the official celebrations. The Moscow city government refused to contribute any money to the affair.
Radical groups announced plans to hold counterdemonstrations. About 10,000 Muscovites organized such an event last year, calling on the Communists to yield power. Mr. Gorbachev was embarrassed and angered last May Day, when radicals took over the Red Square celebration, shouting anticommunist slogans.
The Communist Party and the Soviet military, backed by the Kremlin, have rallied to defend their holiday. ``All attempts to deprive our multinational people of their chief state holiday, which has become an organic part of life in each Soviet home and family, are unlawful and insolvent,'' the Soviet Communist Party declared on Oct. 4. The party press has printed reams of letters demanding the holiday be preserved and interviews with leading intellectuals defending its historical necessity and noble ideals.
Gorbachev issued his own decree commanding the military to hold its traditional parades.
The Moscow Communist Party announced its plans to hold a traditional demonstration in Red Square after the parade. The Army has rolled its tanks into the Baltic capitals, defying the governments by practicing for parades with which they intend to go ahead. ``Thus the military put themselves in the position of an occupying force,'' city official Rein Ratas told Postfactum, a Soviet news agency. Reports from the Baltics predict confrontations.
Moscow also promises to be tense today. The Soviet parliament's leadership issued a call on Nov. 1 for alternate or parallel demonstrations to be held on other days. The Moscow City Soviet defied Kremlin pressure the following day and approved two opposition gatherings, including one to march through Red Square just after the official gathering is over.