"IF I DID NOT exist," Boris Yeltsin has said on numerous occasions, "Gorbachev would have to invent me." Until last week, Yeltsin was surely right: He owed the continuation of his political life to Mikhail Gorbachev's tactical needs. Yeltsin has been to Gorbachev what Medusa's head was to Perseus; when Gorbachev reached into his bag of political tricks and produced Yeltsin, he froze Soviet "conservatives" in fear. Yeltsin made Gorbachev seem supremely moderate, reasonable, well worthy of support.

But last week, Yeltsin was elected head of the Russian republic, the largest of the 15 Soviet republics, and it is probably not the final achievement of this utterly unprecedented Soviet political career. As economic and political conditions in the Soviet Union worsen, and Gorbachev is perceived to be running out of time, Yeltsin, though disparaged by the White House, has been increasingly championed by some Western commentators as the alternative to Gorbachev.

Yeltsin's triumph will allow us at last to see the real Boris Yeltsin, and to judge him by what he does rather than what he says. For despite his assiduously cultivated image of a simple Siberian paren' (guy), he remains a largely enigmatic figure, yet to make public his own detailed blueprint for the future of the enormous republic he now leads.

The Yeltsin mystery stems from the unique nature of his political base: He is the only Soviet politician who enjoys the ardent -- often fanatical -- devotion of the Soviet common man, as well as the solid -- albeit guarded and qualified -- support of most of the intelligentsia. To keep two such constituencies happy requires a great deal of care.

This marriage of reform-oriented democratic "progres-sives" and the Russian hoi polloi is based on their common hatred of the stupidity, rapacity and privilege of the party and government bureaucrats. But it may prove only temporary. And small wonder if it does: Progress and populism are rarely compatible. As Soviet radical economist Nikolai Shmeliov has noted, the most pronounced feature of Soviet political life is its leveling trends, born, Shmeliov writes, "out of the ideology of equality for all in poverty."

A huge segment of Yeltsin's populist constituency consists of social Luddites who are afraid of the havoc, the uncertainty, the need for initiative and self-reliance that radical economic reform will bring. Most important of all, Yeltsin's populism appeals to those who hate the neighbor who does better than they. Yet it is precisely the increased "social layering based on property" that bothers Yeltsin the Leveler. What has been called a key problem of perestroika -- the contradiction between the democracy and the growth of economic inequality -- is bound, sooner or later, to split the Yeltsin constituency. Contributing to the rift between the pro-reform progressives and the populists is the age-old mistrust between the liberal Russian intelligentsia and the narod, the common people, on whose behalf the intelligentsia is supposedly laboring.

Because of the nature of his constituency, Yeltsin is uncharacteristically reticent on the key subject of property. Philosopher Igor Kliamkin notes that Yeltsin talks about the market "through clenched teeth." Thus in his recently published memoirs, Yelstin states that the issue of property divides "the so-called left and right," but does not indicate where he stands on the issue.

Up to now, Yeltsin has proven himself the unsurpassed master of identifying the key sources of public anger and frustration to increase his political momentum. The other pillar of Yeltsin's political strategy, meanwhile, continues to grow stronger. These days, to attack Gorbachev is almost as advantageous as attacking the party itself. As Gorbachev's popularity declines, Yeltsin's critique of him grows progressively sharper and more personal. Perestroika has "failed," Yeltsin told the Financial Times, because "the leadership" failed. Moreover, "five years should be enough for a president to prove his worth." Yeltsin's memoirs cast Gorbachev as "inconsistent" and "timid," a man who "loves" half-measures and "semi-decisions."

Yeltsin seems to regard the political mileage to be gotten out of the "social justice" issue -- the attack on party and government privilege -- as far from exhausted. The single longest topical passage in his autobiography is devoted to the privileges of the top party leadership. Toward the end of the passage, Yeltsin lunges for Gorbachev's political jugular: "Why has Gorbachev been unable to change this? I believe the fault lies in the basic cast of his character. He likes to live well, in comfort and luxury." And -- a twist of the knife -- "what about {Raisa Gorbachev's} Zil limo? My daughter, at her workplace, is given one small cake of soap per month. My wife . . . has to spend two or three hours a day in shopping lines . . . ." When Yeltsin's autobiography is published in the Soviet Union, the paragraph will do more to boost his popularity and sink that of Gorbachev than anything else in the book. In the meantime, Gorbachev -- at least until now -- has continued his cat-and-mouse game: now letting Yeltsin roam loose and even protecting him, now humiliating him. When the "conservative" majority of the First Congress of People's Deputies last May failed to elect Yeltsin to the Supreme Soviet, Gorbachev acceded to -- possibly arranged -- a resignation of one of the elected deputies in order that Yeltsin take his seat. That summer Gorbachev authorized a televised address by Yeltsin to striking miners. When Pravda last fall reprinted an Italian newspaper article that accused Yeltsin of drinking non-stop during his U.S. tour and spending honoraria on jeans and VCRs instead of charities, Gorbachev sacked the editor.

Yet just a few weeks later, Gorbachev humiliated Yeltsin during a televised session of the Supreme Soviet. He had the minister of internal affairs report on a bizarre incident: Yeltsin, the minister alleged, appeared late at night and soaking wet at a police station in the exclusive country retreat of the Moscow elite, stating that he had been kidnapped and thrown off the bridge by unknown assassins.

Yeltsin said later that he himself had concealed the episode for fear of provoking protest strikes and riots by his supporters. At the time, though, his response in the Supreme Soviet was suspiciously confused: He said that nobody had tried to harm him and that the whole episode was "his private life." (A rumor began circulating in Moscow that he was visiting his mistress, who threw a bucketful of water over him.)

Yeltsin's detractors are not confined solely to the apparat. Some in the Moscow intelligentsia are skeptical, even alarmed. According to the liberal literary magazine Novy Mir, they see in Yeltsin a "neo-Bolshevik," the "central point" of whose program -- redistribution of goods and services accumulated by the ruling class -- was "the leitmotif of all Bolsheviks." His program, the article reports, is seen by some as a "collection of primitive quasi-solutions."

The Moscow intelligentsia is heavily overrepresented among the sources of Western correspondents in the Soviet Union, so its weariness of Yeltsin permeats Western media. Nonetheless, the intelligentsia's attitudes are themselves somewhat suspect.

Perhaps nowhere in the world does there exist a more snobbish intelligentsia than in Moscow. A wrong accent, a gesture that is not comme il faut, or (God forbid) a grammatic deficiency are all valid reasons for excommunication. (Although Gorbachev speaks better Russian than any Soviet leader since Lenin, he too has taken his lumps. His fall from grace began when, during the televised proceedings of the First Congress of People's Deputies last summer, he several times used the incorrect third person plural form of the verb klast, to put down.)

A son of a Siberian peasant, Yeltsin can hardly count on acceptance by Moscow intellectuals. In his book, Yeltsin notes that Moscovites "make no attempt" to hide their "snobbery and arrogance" toward provincials and that, prior to his move to Moscow, his rare encounters with the inhabitants of the capital left "a nasty taste" in his mouth.

Another, more powerful source of the intelligentsia's resentment is deeper and perhaps subconscious. For generations, it cast itself as fighters and martyrs for the common folk. But, with a few notable exceptions, the intellectuals know nothing of them. They do not know how "the people" live, do not share their habits, and (except in books) do not speak "the people's" language. Yeltsin, on the other hand, is a voice of the Soviet masses, and therefore a threat to the intelligentsia's exalted status. Doubtless the thing that most fascinates many Westerners about Yeltsin is the use to which he might someday put his populist following, and the direction in which he might take Soviet politics.

Today, the central, most fateful aspect of Soviet political life is a desperate race between two parallel processes: the disintegration of the Soviet economy, and the emergence of new political structures enjoying popular support and consent. If the former outpaces the latter -- if the economy collapses before a legitmate central government is installed -- then this giant land, this military "superpower" in possession of over 12,000 nuclear charges, is likely to plunge into violent political chaos, a Lebanon-like war of all against all.

The Soviet Union's only chance to win its deadly race is a government vested with authority and having enough legitimacy to administer the very bitter pill of radical economic reform. The creation of such a government is the central and most urgent issue of Soviet politics today. Gorbachev's much-touted "grab" for the "emergency powers" of the presidency is thus irrelevant. Indeed, his "emergency" power may best be compared to that of the captain of the Titanic.

The only means of creating a legitimate government is for Gorbachev to dissolve the Congress, resign the presidency and proceed with direct multi-party national elections of a new parliament and a new president. And Gorbachev may well be reasonably assured of gaining the presidency -- if Yeltsin decides not to challenge him. In that case, Yeltsin could savor the exquisite revenge of watching his nemesis struggling as the head of a disintegrating Soviet Union.

If such elections do not materialize by the end of the year, three other scenarios suggest themselves. The first is a democratic, procapitalist revolution that would finish what Gorbachev started but took too long to complete. The second is an authoritarian, anticapitalist, anti-Western, "neo-Bolshevik" revolution. And third is a KGB-military junta of "national salvation." While Yeltsin's role in the third case is hard to imagine, except as that of a victim, he is well-positioned to occupy a prominent, perhaps even central, place in the other two.

In public opinion polls a few months ago, Yeltsin was second only to Gorbachev in popularity, while his "negatives" were slightly lower than those of the president. He has little-advertised but strong and growing ties to the military -- another source of the intelligentsia's concern. During his campaign for nomination to the Congress of People's Deputies, Yeltsin was ferried about the country in military planes. He is a key organizer of the Democratic Front, one of whose institutional members is Shebit (or Shield), a union of radical "left" officers. A Russian revolution led by the junior military, like the 1975 revolution in Portugal, is a very plausible sub-scenario of a democratic revolution. But would Yeltsin lead a populist revolt? His critics say he very well might. They point out, for example, his flirtation with Pamyat, the nationalist, neo-Bolshevik organization whose representatives he met during his tenure in Moscow. (Yeltsin claims that he met with the Pamyat demonstrators, who occupied Red Square, only because he wished to defuse a tense situation and prevent police crackdown.) A more serious, and persuasive, argument in favor of Yeltsin-the-authoritarian stems from the ill-defined nature of his objectives. What does he want beyond the elimination of privileges, the dissolution of the apparat, and the effective abolition of the party monopoly on power? The character of his constituency and its mood give rise to gloomy predictions, like those of Andronik Migranian in Novy Mir.

"The past is shameful, the present is monstrous, and the future cannot be defined, cannot be predicted. In such a psychological state the masses are ready to accept any leader who will say; 'I know what to do and how to do it.' And . . . the Yeltsin phenomenon . . . is explained by this psychological condition of the people . . . . The popular mood that has made Yeltsin the populist leader is very dangerous . . . . Further deterioration of the general situation in the country will further widen the circle of the "decisive" people ready to support any leader offering simple, quick and effective decision in the name of social justice. {But} the course on re-distribution of the present goods is a course into the blind alley of a new slavery. Soon there will be nothing left to redistribute. And terror will follow."

In speeches and interviews in the United States last September, Yeltsin repeated over and over again that Gorbachev has at most a year to improve the economic situation -- or vacate the space at the top for a more successful politician. "If not, then what happens?" asked Jim Lehrer last September. "A revolution from below will begin," answered Yeltsin.

Half a year later, Yeltsin told the Associated Press, "The time of compromise and half-measures is past. We are sitting on top of a volcano, and very soon neither Gorbachev nor anyone else will be able to control the events. The people will take their fate in their own hands, as it happened in Eastern Europe. If we are lucky, everything will happen orderly, as in {East Germany}, Czechoslovakia and Bulgaria. But what happens if the situation develops in the Romanian pattern? Bloodshed? Tragedy?"

"Would you like to be president of the Soviet Union some day?" Jim Lehrer pressed him. "It's a possibility," Yeltsin answered, "if I am not too old and have strength.'

Samuel Johnson is said to have remarked about Lord Chesterfield: "This man, I thought, had been a Lord among wits, but, I find, he is only a wit among Lords." Only time will tell whether Boris Yeltsin is a democrat among the populists or only an authoritarian populist among the democrats. We may not have to wait long to find out.

Leon Aron is a senior policy analyst in Soviet studies at the Heritage Foundation. This article is adapted from the summer issue of The National Interest, to be published June 10.