The last episode of “The Jewish Americans,” the three-part series that aired on PBS in January, included an impassioned segment on the campaign to free Soviet Jewry. Now comes “Refusenik,” an entire documentary devoted to that remarkable slice of history.

Drawing on 108 interviews conducted by director Laura Bialis, crammed with rare and incredible news and amateur movie footage and running nearly two hours, “Refusenik” is a broad, comprehensive document that will stand forever as a major contribution to the record.

But while its historical and educational value is substantial, the film is unexpectedly lacking in drama and emotion. Episodic in its approach and literally all over the map, “Refusenik” sacrifices suspense, momentum and a good deal of power in its zeal to touch every base.

Nonetheless, Soviet Jews who immigrated to the U.S. and Israel in the last two decades will be especially touched by the film, which recalls the hopelessness of the dark years behind the Iron Curtain and conveys the elation of achieving an impossible dream.

“Refusenik” opens April 11 at the Lumiere Theatre.

The film opens with a glimpse of the Soviet Union under Joseph Stalin after World War II. Perhaps stung by the new state of Israel’s embrace of the U.S. — despite the eight planes he provided in time for the ’48 war — the dictator cracked down on Jewish professionals. The infamous doctors’ plot, along with anti-Semitic coverage in the press, made Jews fearful that Hitler-style extermination camps were in the offing.

Those concerns died with Stalin in 1953, but his successors discouraged the practice of Judaism and destroyed any positive associations with Jewish identity. It was a form of “spiritual genocide,” according to one of the American Jews involved in the founding of the Student Struggle for Soviet Jewry in 1964.

Elie Wiesel’s visit to the USSR, and his 1966 book “The Jews of Silence,” helped fuel the campaign. The following year, the Six-Day War transformed Soviet Jews from frightened to proud overnight. A letter made its way to the West with a plaintive question: “Why have you forgotten us?”

The grassroots movement in the U.S. was propelled by students, housewives and Holocaust survivors, the last group having firsthand experience of the world’s indifference. Meanwhile, the 3.5 million Soviet Jews grew so desperate that a few brave men and women took extraordinary measures, especially after it became common knowledge that an emigration request meant the loss of one’s job.

“Refusenik” diligently devotes time to every milestone on the road, from the arrest and trial of the Leningrad hijackers (who planned to take over a small jet and fly to Finland), to the arrest and conviction of Natan Sharansky on the absurd charge that he was a CIA spy, to the pressure on Leonid Brezhnev and Mikhail Gorbachev marshaled by Sen. Henry “Scoop” Jackson and eventually applied by Ronald Reagan.

But any momentum the film builds is dissipated by its continual skipping between the Soviet Union and the U.S. — along with the occasional trip to Israel. And while the interviews are uniformly engaging, the very fact that the protagonists escaped the Soviet Union and can tell their stories drains most of the danger and tension from the film.

“Refusenik” raises two very interesting points, almost offhand, that deserve more investigation. For one, it implies that the extended battle inside and outside the Soviet Union to free Jews might have created the fissures that led to the fall of communism and the demise of the Soviet bloc.

Second, while young people and other ordinary citizens — including many non-Jews outraged by human-rights abuses — propelled the movement to free Soviet Jewry, the Jewish establishment was slow to get on board. Was it institutional conservatism, or a conscious reluctance to speak out on any area of U.S. foreign policy other than support for Israel? And are there any lessons that mainstream Jewish organizations might apply today?

“Refusenik” opens April 11 at Landmark’s Lumiere Theatre in San Francisco.