(FORTUNE Magazine) – Nexis, as ever our guide to ideas in the wind, confirms that a large new question has been laid on the table. It concerns legitimacy. Here we allude not to the marital status of various folks' natural parents -- an issue in % some danger of becoming a non-issue -- but to this breathtaking question: By what right does the Communist Party run the Soviet Union? Is the party's rule legitimate? For the first six months of 1988, Nexis reports 50 sightings of ''legitimacy'' within 30 words of ''Communism'' or ''Communist.'' In case you are wondering about the baseline situation, Nexis notes that the score for the first six months of 1984 was an extremely ovoid zero. Legitimacy is a concept that political scientists find at once elusive and enormously important. According to the International Encyclopedia of the Social Sciences, the term refers both to ''a consciousness on the government's part that it has a right to govern and . . . some recognition by the governed of that right.'' Down through the ages, rulers of every kind have felt a need to address the deadly question -- by what right do you rule? -- and have come up with quite varied answers. Kings and Pharaohs have ruled in the name of God, Hitler in the name of the Aryan race, democratic executives in the name of the people. Lacking some kind of sustaining myth, a regime may still try to hold power by naked force, but the footing is inevitably treacherous when you command loyalty from neither subjects nor subordinates. So folks in the dictator business are naturally not too eager to admit that their right to be on top is morally equivalent to Al Capone's right to run the beer business in Chicago in 1926. This brings us to the Communist Party of the Soviet Union. The party's legitimizing idea has been the Marxist-Leninist ideology, which casts the party as the embodiment of a triumphant working class, destined by history to prevail worldwide as the capitalist enemy collapsed in its own contradictions. The idea always had quasi-religious overtones, fortified by the cult of Lenin and millenarian notions about Communism's paradisal future. Although unsustainable on any factual level, these notions had a certain mythic power as recently as the mid-Seventies. To be sure, there were always a few ungenerous Sovietologists who found the regime easier to understand via the Capone model. In an article published in 1964, Adam Ulam of the Russian Research Center at Harvard referred quite respectfully to certain colleagues who insisted that you could learn a lot about Soviet politics by studying the struggles between Al Capone and other gangsters. Is it not significant, fellow neoconservatives, that we have seen this passage quoted twice within the past couple of months? It is not too hard to analogize between the Soviet Union and a large company taken over by the mob. In both cases the victim just gets sicker and sicker. In both cases the parasitic group in charge of things lives splendidly, and everyone else is in boundless trouble. In the Soviet Union the three million or so members of nomenklatura families live like kings. Their privileges include chauffeurs, dachas, splendid apartments. Meanwhile, the average Russian has a living standard equivalent to Italy's around 1950. So you do not need to be a poly sci Ph.D. to gravitate to the deadly question. What gives Communists the right to inflict socialism on the Soviet people? Mikhail Gorbachev clearly understands a lot of this, but he looks to have many of the problems of a mob bigshot trying to go straight. It's not easy, and the Sovietologists we most respect leave us thinking that his solutions are only making the deadly question harder to answer. This is the judgment of, for example, Leopold Labedz, editor of London-based Survey, a journal about Soviet affairs. Labedz views Gorbachev as a man who lacks a strategic plan and is desperately improvising. He has just about given away the Marxist-Leninist argument for the regime's legitimacy. (Even Lenin has been criticized in the Soviet press lately.) Yet Gorbachev cannot claim to have replaced the old-time religion with democratic legitimacy; and meanwhile, the sudden whiff of freedom in the Soviet Union is leading to all sorts of unbelievably subversive thoughts getting uttered aloud. On the day we are composing this item, the Washington Post features on page one the recent adventures of a Soviet group called Democratic Initiative. A member of the group has given the Post a videotape of a recent rally in Magadan. The rally's high point, on our scoring, came when a speaker pointed to a splendid building, known locally as the White House, where party leaders live. ''Over there,'' he says. ''That's where the mafia lives.'' Would he have dared talk that way about Capone? One wonders.