The Polish election results last Sunday were an enormous jolt to the country. As expected, Poland's charismatic leader Lech Walesa came in first, though with less than half the votes. Shockingly, Prime Minister Tadeusz Mazowiecki -- who had secured Poland's borders in a historic treaty with Germany, and whose economic team had set in motion the most far-reaching program of economic reforms in Eastern Europe -- was sent to a humiliating third-place finish, coming in well behind an unknown Polish-emigre businessman, Stanislaw Tyminski. Walesa is the heavy favorite against Tyminski in the runoff elections in two weeks.

Mazowiecki's defeat was a painful end to a task that was surely thankless from the beginning. As the region's first non-Communist prime minister, Mazowiecki inherited a hyperinflationary, chaotic economy that was the worst in Eastern Europe. He showed remarkable courage in supporting the tough economic reforms of his finance minister, Leszek Balcerowicz.

These reforms successfully tamed the hyperinflation, created a convertible currency and established free markets and hundreds of thousands of new private businesses in the formerly planned economy. But the sudden switch to a market economy also raised profound anxieties, as most households throughout Poland wondered whether they would be able to stay afloat -- much less prosper -- in the new system.

The anxieties gave root to feverish and often extravagant fears that have gripped the Polish society this year. Mazowiecki, a lackluster communicator, was unable to combat these fears, and they contributed to his electoral debacle. There has been a persistent -- and totally erroneous -- forecast of a 20 percent unemployment rate, though the unemployment rate now stands at 5.5 percent, less than in the United States. Similarly, fears of plummeting take-home pay abound, though the average industrial worker earned $131 per month in October 1990 compared with $108 per month in October 1987.

Walesa sensed these deep fears throughout the country early in the year, and with his deft political touch harnessed them into political support on his way to the first-place finish Sunday. Rather than defending the government's tough economic policies -- as Mazowiecki had counted on -- Walesa criticized the government as insensitive to the common man's insecurity and argued that only with himself as president would the Polish society stay the course of change. Tyminski -- who to this date remains a shadowy figure with reported contacts to Libya, the Polish Communist Party and Canadian extremist politics -- went far beyond Walesa, telling the struggling families in rural Poland that Mazowiecki was turning the Poles into the "white slaves" of Europe.

Many of Mazowiecki's supporters are frightened that the election results signal the country's descent into an orgy of populism at one of the pivotal moments in Poland's history. This conclusion is understandable from embittered Mazowiecki loyalists, but it is surely too glib. There is an excellent chance that Walesa is right when he maintains that his remarkable political instincts will actually be the key to keeping the reforms on track.

Without doubt, Walesa's goal is the same as Mazowiecki's -- a capitalist Poland within the mainstream of Europe. Even in the 1980s, when many in the anti-Communist movement were flirting with the idea of a "socialist market economy," Walesa was speaking clearly about the need for a capitalist system based upon private ownership. And more to the point, Walesa's campaign aides have made clear -- at the cost of votes lost to Tyminski -- that they expect to keep Balcerowicz in the job of chief economic manager in a Walesa government.

Not that the risks aren't present for a populistic explosion. Ironically, if Mazowiecki's supporters fail to rally quickly to Walesa, Walesa may be forced to retreat into political deals with more extremist or desperate parts of the society. If Tyminski continues his remarkable political ascent, he could push Walesa into a corner or even (though the odds are very long) catch him in the second round.

The West should be ready to respond with vigorous support to a Walesa presidency. Of course, Western governments should start by making clear that they have no time for populist dead ends in Poland. But it is even more important that Western leaders make clear to Walesa and to the Polish people that the West will help to see that Poland's brave reforms pay off: by ensuring Poland's access to Western markets for Polish exports, by finally arranging a reduction of the $44 billion in foreign debt run up by the Communist regime, and by promising that if Poland remains stable and democratic it can look forward to full membership in the European Community by the end of this decade.

The writer, a Harvard economics professor, is an adviser on Poland's economic reforms.