During Black History Month rather than on the January national birthday holiday, the Museum of Modern Art offered the three-hour King: A Filmed Record . . . Montgomery to Memphis. Why this Oscar-nominated documentary so seldom sees the light of day is baffling: forty-one years later, it still brings cheers and tears and shows what we might be.

A sole quibble with the Mankiewicz-Lumet gem is the fourteen ultra-famous entertainers -- including Charlton Heston, whose early good works have been forgotten -- posed to intone solemnly. These “bridges” are distracting and, apart from Harry Belafonte’s opening, were excised from the ninety-minute TV version. (There exists a theatrical print of one fifty-three.) One sees enough of mega-celebrities, anyway, in unobtrusive snatches in the archival footage.

In an unintended way, however, the famous do underline the charisma of the Rev. Dr. Martin Luther King, Jr., for their stiff readings from other King speeches fall flat in the face of the rest, largely footage of him delivering his own. The funeral prayer of constant companion Rev. Ralph Abernathy, too, fails to match the sweep of the man. King’s style was exceptional but derived from the preacher’s at its peak, and from whatever pulpit, dais, sidewalk or hall, the cadences and emphases, the pauses, flourishes and Biblical parallelism move the very stones. Not until nearer the end is the outward public figure shown laughing, informal, at ease, then to reveal the harried, tired and instinctively frightened human being who would not succumb to fear. On a rarely seen private flight, not long before the also- and often-shown speech that last evening before the Lorraine Motel balcony, he talks of death but will not waver. “I have the capacity to die.”

The presence, the voice and style carry the burden. Effective as it is, for example, the Letter from a Birmingham Jail seems less when read aloud by another against stills of “the moral leader of our nation” behind bars. The tone and meaning, not of voice but of film and man, is cast from the outset, with young fire eaters advocating self-defense, physical force, eye-for-an-eye blood, alternating with King’s reiterating love, “soul force,” turn-the-other-cheek passive resistance.

There is no narration. None is needed, although subtitles identify dates, places sometimes people. Few documentaries depend as strongly on one personality, one face, as this, tracing in his own spoken words the spirit and the Movement from the 1963 Birmingham bus boycott, through major and lesser-known events, to the 1968 Memphis sanitation workers’ strike. There are other recognizable faces, and there is the music -- Soundtrack for a Revolution appeared on the birthday a year ago -- and the singers, church choirs (including Coretta Scott King) and hand-clapping driving gospel, jazz, folk and pop, at marches and rallies, and the anthems sung by millions. And there is the news footage that is hard to watch even today, of fire hoses and police dogs, tear gas and bombings, billy clubs, cattle prods and Black Marias. Some references have been lost to time, such as the subtitle identification -- wildly cheered in 1970 -- of Al Hibbler (“Unchained Melody”) as the target of “Bull” Connor’s racist epithet.

Before social media but like stirrings in Tunisia, Egypt and elsewhere -- Bahraini demonstrators are carrying portrait placards of Dr. King -- this was an idea whose time had come, personified in its uncompromising leader. Injustice infinite, each goal achieved, others were added. Dr. King expanded SCLC objectives, from city- to interstate-transportation and lunch counters to education and voter rights, from equal political say to public facilities, housing and economic opportunity, from denunciation of racial, ethnic and religious bigotry to an anti-Vietnam War stance. What today seems so logical a progression was a revolution then, transforming America and the world.

Greeted with applause, a mid-original-print announcement indicated that 1970 movie theater owners and employees were donating profits and earnings from the showing to the Martin Luther King, Jr., Foundation. Produced by Ely Landau for that Foundation, KFRMM was in 1999 elected by the National Film Preservation Board to the Library of Congress National Film Registry of “culturally, historically, or esthetically significant” Americana.

The King is dead. Long live the King!

(Released by Maron Films; not rated by MPAA.)