Greece's Socialist prime minister, Andreas Papandreou, conjures up sharply contrasting images among his friends and foes, but for both he remains the ultimate enigma.

To his followers he represents what the electorate has long wanted: a leader with charisma in a country that likes its leaders in primary colors; an understanding of economics and a command over a strong, disciplined party capable of carrying out long overdue structural reforms.

For them, he is looking out first and foremost for Greece and refuses to be pushed around by the United States, whose only interest they believe is the military bases it maintains here in an outdated rivalry with the Soviet Union.

To his detractors, Papandreou, 63, comes across as an authoritarian who shifts his ground, whose commitment to democracy and the West is suspect and who has concentrated all real power in his own hands, effectively controlling defense, foreign and economic power and refusing to delegate authority.

His friends see in him the modern man who has swept away the older politicians whose thinking congealed in the 1950s before the country responded to economic growth and social change.

His adversaries only see an embittered man of the 1960s still clinging to that era's taste for outrage--in the United States and in Greece, where he seems convinced that American power corrupted institutions.

Papandreou was jailed, then sent into exile by the military junta that seized power in 1967 to frustrate what he say would have been a triumph of his father's party in scheduled elections. He returned to Greece even further radicalized seven years later when democracy was restored.

From 1939 to 1959 he had lived and prospered in the United States as an American citizen and respected economics professor. That experience has made him neither totally American nor totally Greek and has nurtured a reputation for unpredictability that keeps politicians, diplomats, businessmen and analysts fascinated.

George Rallis, the New Democracy prime minister Papandreou defeated last fall, described his rival as a man who "can tell you today the sun is shining and the next day say he never said that and indeed had said there was a full moon. And he is not ashamed to look you in the eye knowing you know he is lying."

Rallis spoke without rancor and even with a hint of hope that the exercise of power would sober Papandreou and turn him into the statesman he has long seemed destined to become, at least by birth and training, but perhaps not by disposition.

Those who claim to understand Papandreou are less worried about the detractors' image of the prime minister as the "new Satan" than a certain brittle frailty, an inability to accept the rough and tumble inherent in democracy.

That shortcoming first came to light when his party lost the 1961 election and he cried foul. "That was his Greek political baptism of fire," an old friend recalled, "and he just couldn't accept that in fact he had lost fair and square."

The real question is whether he has outgrown that worrisome trait or whether it will return when the going gets tough and destroy both him and the hopes of a new, democratic Greece.