FORTY-SIX years ago today, Japanese bombers caught America with its pants down at Pearl Harbor. A more subtle version of the Japanese's surprise attack seems to be replaying itself today.

In a town dominated by political showmanship and drama, Soviet General Secretary Mikhail Gorbachev should feel right at home this week in Washington. An atmosphere of "hopeful expectataton," created by the press and a weak Administration, awaits the first visit of a Soviet leader to the United States since 1973.

Gorbachev's popularity in the United States has gained so much that he could probably blow away the Democratic presidential field in any election or debate. But before Americans roll out the red carpet, they should snap out of the charismatic spell he has cast and look realisticly at a Soviet leader who is following the policies of his predecessors.

FOR ALL his talk of "glasnost" and "perestroika," Gorbachev maintains the iron hand of authoritarian government. The communist regime still does not grant its own citizens freedom of speech, association or the press. Thousands of Soviet citizens continue to fill Russia's jails, mental hospitals and slave labor camps because of their political and religious beliefs.

Soviet brutality and blatant disregard for human rights was sharply brought into focus yesterday when Moscow security police beat and arrested CNN's Moscow bureau chief for "assaulting a Soviet citizen." The Kremlin must be complimented on its novel way of describing a journalist watching a refusnik protest. For most Russians, such incidents are a part of everyday life.

Nor have "liberalizing reforms" or "restructuring" occurred in Eastern Europe, which still lies in the grasp of communist political and military domination. Moscow has not loosened its grip on its Eastern European satellites and continues to force their contributions to the Warsaw Pact's military buildup.

The Warsaw Pact leads NATO in all conventional weapons and outnumbers NATO forces in Western Europe by two-to-one in men, tanks and artillery. On the important central front in West Germany, Soviet tanks are five times more numerous than NATO forces. Gorbachev has only hinted at possible negotiations on conventional weapons, and only after he has succeeded in reducing INF and strategic nuclear forces--NATO's only counterbalance to Soviet tanks and troops.

And make no mistake about it, the Kremlin is continuing its massive investment in offensive strategic and theater nuclear forces, as well as in conventional land, sea, and air forces that go far beyond any legitimate defense needs. The Soviet military already is beginning deployment of newer and more dangerous weapon systems: the Delta IV missile submarine, the Blackjack supersonic bomber, and the SS-25 mobile ICBM. Even if Gorbachev is sincere about his desire to devote resources spent on the military sector to the civilian economy, he has not been able to control or convince his military.

MR. GORBACHEV has, however, played the good salesman, preaching the virtues of peace, disarmament and the Soviet way. He has even written a book, published by Harper and Row, to let Westerners in on his plans of perestroika.

But what is Gorbachev really hawking? Many Americans gloat that INF will force the Soviets to destroy more missiles than we will. But these observers fail to see the treaty's strategic and political significance. The INF treaty is not the bargain it seems because an increasingly denuclearized Europe favors the Soviet advantage in conventional weapons--allowing the Kremlin to use its military superiority to threaten the West in a crisis. The removal of the Pershings will breed NATO infighting over who will bear a heavier defense burden and may portend an eventual American pullout from Western Europe.

Events in Nicaragua and Afghanistan are not conciliatory gestures, but shrewd political manuveurs. It is estimated that the invincible Red Army is incurring casualties in Afghanistan as high as those we did in Vietnam, while Nicaragua has become an enormous military and economic drain on the rickety Soviet economy. Gorbachev wants out in both places, and he needs American help to ensure that rebels will not topple his puppet governments when he leaves. By agreeing to stop funding the contras and mujahadeen in exchange for vague promises of more arms agreements, the Unites States would give legitimacy to the Marxist regimes in both countries that have killed thousands or even millions of their own citizens.

Stalin and Khrushchev would be proud of Gorbachev, who is no different in his attempts to strengthen the Soviet economy and expand Soviet influence throughout the world. He is only the first General Secretary with enough Western-style charisma to wow the world community. He has taken the initiative by pouring forth a deluge of proposals for arms reduction, making the United States appear inflexible when we don't accept them.

Worst of all, Gorbachev has taken advantage of Reagan's hopes to revitalize his wounded presidency. The administration's stand-tough policy on missiles in Europe and aggression in Afghanistan and Nicaragua forced. Gorbachev to the bargaining table. Now Reagan may throw that all away by trying to wrap up an agreement that will give him a place in history. Unfortunately, that place may be one distinguished by the hegemony of the Soviet Union and the decline of the United States.