"Reds," the biographical epic set in the years 1915-1920, attempts to chronicle a storm-tossed romance set against the intellectual and political turbulence of the era. On paper, the movie suggests a dramatic improvement on "Dr. Zhivago" -- an American romance, inspired by historical fact. The lovers, radical journalists John Reed and Louise Bryant, portrayed by Warren Beatty and Diane Keaton, are magnified by their involvement in momentous events, notably the Bolshevik triumph in revolutionary Russia in November of 1917. On screen, "Reds" evolves into an earnestly muddled mishmash of Romance and History. An intriguing, ambitious disappointment, it launches the Christmas movie season on a note of droopy-spirited seriousness.

"Reds" isn't solemn from the outset. Indeed, it gradually reverses tone, beginning at the glib end of the scale and concluding at the doleful. The wayward tone may be a clue to Beatty's uncertainty about the audience. One detects a lack of confidence that the public will sit still for complex character development or prolonged discussion of the political issues that agitated the activists of Reed's generation.

"Reds" is better equipped to stir a studious interest in Reed and his contemporaries than to satisfy conventional dramatic expectations. Ironically, the most evocative aspect of the presentation is a documentary enhancement -- interviews with a number of venerable "witnesses," whose recollections of the period help to set the scene, bridge transitions and preserve a touching human perspective.

The movie opens with an eloquent fragment of reminiscence by a "witness" unknown to me. "All of us, after all, are victims of our time and place," she says, and this casual remark suggests a theme appropriate to the story of John Reed and Louise Bryant. A minor complaint: Beatty never does identify individually these wonderful old commentators, a number of whom have died since he recorded their impressions. A few faces may be recognizable -- Henry Miller, Adela Rogers St. John, Rebecca West, George Jessel -- but most are not, and it would be gratifying to know exactly who's who.

Beatty and Keaton are first encountered in Portland, Ore., at the end of 1915. Reed, a native of Portland and already a famous journalistic figure by virtue of his ardent coverage of the campaigns of Pancho Villa and his disapproving dispatches from the war zones of Europe, has returned home for a holiday visit with his widowed mother. Bryant, the restless, artistically pretentious wife of a local dentist, buttonholes Reed after he makes an appearance at the Liberal Club, where he spoils the party by criticizing the war.

A request for an interview -- Bryant's avocations include a spot of reporting for a local weekly -- leads to a night of conversation, in which Beatty makes light of Reed's pronouncements on the state of the world by cutting them short with repeated shots of coffee being poured from pot to cup. Comes the dawn and Reed starts to make a pass, which Bryant coyly deflects. It's a pointless delaying tactic, because the evident infatuation is soon consummated in facetious circumstances -- the grounds of a church during evening services, with the choir singing "Onward Christian Soldiers" in the background.

Bryant abandons her husband to take up residence with Reed in Greenwich Village, depicted as a dizzy whirl of parties and political conversation. The dramatic priority is supposed to be Bryant's resentment at being the new girl in heady Bohemian surroundings -- the pretty adornment no one takes seriously. Bryant is intimidated by Reed's celebrity and his highbrow circle of radical friends. Edward Herrmann appears as Max Eastman and Maureen Stapleton as Emma Goldman, a splendid performance in a role that deserves to be expanded. Bryant does a slow burn and indulges in shrewish tantrums.

Nevertheless, the heroine's sulks and outbursts seem to pose less of a problem than Beatty's skittishness as a director. He cuts compulsively from snippets of carousing to snippets of talk and turns the whole atmosphere of literary Bohemia into a breezy blur.

The incessantly fleeting style of depiction leaves one ill-prepared for the first big shouting match between the lovers. Watching this theatrical set piece, I suddenly realized that I hadn't begun to think of Reed and Bryant as a couple intimate enough, sexually or emotionally, to get into a showy verbal dust-up. Beatty's pace becomes ponderous in the closing stages of the movie, which runs an expansive 199 minutes.

The first sequence that really sustains dramatic interest is dominated by Jack Nicholson, who contributes a commanding performance in the relatively small role of Eugene O'Neill, who had a clandestine affair with Bryant in the summer of 1916, when many of the Villagers were vacationing in Provincetown, Mass. and an O'Neill one-acter, "Bound East for Cardiff," became the first triumph of an experimental theatrical company called the Provincetown Players. Coming on to Keaton, Nicholson projects a smoldering sexual intensity and cynical charm that remain the strongest single identity in the film.

Unfortunately, Nicholson makes O'Neill such an insinuating, magnetic presence that one may be reluctant to play along with the necessary romantic point -- Bryant and Reed were the true love match. Their reunion as partisan journalistic witnesses to the climax of revolution in Russia is meant to reaffirm a bond weakened by lovers' quarrels and betrayals. In fact, it tends to suggest a bond for the first time. Keaton doesn't seem to look at Beatty with much regard until they're caught up in the fervor of a mass meeting and Reed is asked to address the hospitable throng.

Beatty and his screenwriting collaborator, the British playwright Trevor Griffiths, were faced with a curiously unconventional and elusive love story. Less than five years passed from the day in 1915 when Reed and Bryant met in Portland to the day in 1920 when Reed, a victim of typhus, died in Moscow, with Bryant at his bedside. They were separated or estranged during a good deal of this time, as competing careers or recurrent misunderstandings conspired to keep them apart. And yet the evidence suggests that the neglect was ultimately transcended by genuine devotion. Moreover, tragedy seems to have dignified their unstable courtship and marriage. There's something undeniably heroic and stirring about Bryant's effort to reach Reed in the embattled Soviet Union in 1920. They were reunited for the last time two weeks before Reed's death.

Although Beatty's tendency to compress political debate into a verbal buzz of argumentation is a trivializing annoyance, the movie is undermined by his failure to rise to the peculiar grandeur of the love story. The political talk is frequently rushed, but it's also literate and eloquent on many occasions. What remains superficial is the love story, which expires in drabness when it needs to get you there and lift you up.

The surprising weakness is not that Beatty and Keaton seem too lightweight to impersonate literary characters but that they seem too lightweight and disconnected to embody a merely picturesque, conventionally touching romance. Keaton, I suspect, is compromised by confused, expedient tendencies in the script. For example, I was thrown for a loop when Bryant was used to scold Reed for getting fanatic about his organizing for the embryonic American Communist Party, then a splinter faction within the Socialist Party. I was under the impression they returned from Bolshevik Russia seeing eye to eye politically. Unless I miss my guess, Keaton's billowy gowns and hats are going to make a bigger impression than her testy, stubbornly unlovable characterization.

Beatty may have spread himself thin between various executive and artistic roles. "Reds" is the culmination of a creative urge sustained for better than a decade. Given this obvious dedication, it's dismaying to find the leading performance so deficient in animal or intellectual magnetism. Before I saw the movie I thought I understood why Beatty wanted to portray John Reed. At once an inspirational and cautionary culture hero of the Left, Reed embodies the political passions of the World War I period in ways that suggest affinities with the Vietnam period. When the movie did its last fadeout, I wasn't sure why Beatty had been drawn to Reed. Why did he need to impersonate this particular man if the emotional affinities appear so nebulous? It isn't the running time alone that makes "Reds" a tough sell and a discouraging endurance test; it's the lack of an emotional payoff strong enough to justify an epic trek down the corridors of history.