"The Last Supper," evidently the prestige attraction of a recent cycle of Cuban movies at the Key, would not persuade one that great things were happening in that outpost of tendentious filmmaking. Not that I'm inclined to believe in the beneficent influence of a revolutionary prolitical ideology, especially Marxist-Leninist ideology, on the artistic impluse or vocation. True allegiance to the latter will always conflict with true allegiance to the former.

An ambitious but turgid historical drama, "The Last Supper" betrays hardening of the artistic arteries in Tomas Gutierrez Alea, who achieved an international reputation with "Memories of Underdevelopment," an admirable character study of a superflous bourgeois in the aftermath of Castro's revolution. "Memories" seemed unusually introspective and compassionate, genuinely interested in the emotional dilemma of someone who finds himself out of sync with history.

By comparisons, "The Last Supper" is cut-and-dried, dogmatic dramaturgy, ultimately more interesting as a clue to Cuban propaganda aims in the so-called Third World than as a discreet or even national work of art.

Although Alea seems to bedrawn to the mentality of characters who represent the old ruling classes, he stacks the deck against his ruling class protagonist in "The Last Supper" - a plantation owner who provokes an uprising among his slaves by condescending to fraternize with them during Holy Week. Overcome by a fit of vainglorious piety, he invites 12 slaves to share a drunken Easter feast with the master, then reacts with vicious hypocrisy when they take him at his word and defy the overseer's orders to work the can fields on Good Friday.

Viewed as an ineffectual, self-deceiving fool, the owner might have evolved into a memorable satiric figure. Here he runs the gamut from fathead to tyrant, not a very edifying progression. What might have been rather effective as a droll parable, a more politicized variant on Bunuel's "Viridiana" and "The Discreet Charm of the Bourgeoisie," degenerates into melodramatic claptrap.

The story climaxes ininsurrection and massacre, with the heads of slaughtered slaves displayed on pikes at master's barbarous Easter Sunday service. The effect suggests a low budget "Spartacus." Alea must have indulged a long-standing weakness for that panorama of all the crucified slaves lining the backlot at Universal.

He also ends on a Note of Hope rather less respectable than Hollywood's form of consolation - the infant son of Spartacus. "The Last Supper" closes on a series of lyrical vistas of one slave escaping into the hills, a totally arbitrary revolutionary upbeat, especially in view of Alea's failure to identify closely with any of the slave characters.

"The Last Supper" isn't really dramatized from the point of view of the submerged class in the story. It's a politically complacent, predictable caricature of the ruling class of two centuries earlier. Moreover, the set piece of the story, the master's Last Supper party, looks so static and stagey on screen that one suspects it might be more effective on the stage. There's an awful lot of speechifying for an awful long stretch.

Ideological purity often wins undeserved brownie points for foreign directors. The overrating of European plodders like Fassbinder and Herzog is realted to a considerable extent to the obvious left-wing sentimentality permeatn their outlooks. Even when the political bias of the filmmakers results in crude distortions, as it does in "1900" or "The Battle of Chile" or "The Last Supper," the prevailing tendency is to assume that such liabilities flow out of an excess of honest indignation or sincere social consciousness.

Ironically, the lotus-from-the-mud achievements of an inspired American outsider like low-budget horror filmmaker George Romero seem to have greater integrity and pertinence, in both artistic and social terms. Working with rigid commercial and genre constraints in pictures like "Night of the Living Dead" and the current "Martin," Romero nevertheless achieves an imaginative liberation, formulating a distinctive visual style along with a distinctive view of social reality.

It appears that Alea, nominally the more committed artist, may find his artistry increasingly diminished by the inherently anti-individualistic nature of the ideology he's committed to.