The film itself signals some of the reasons for why communism was in crisis in the 1980s. Official corruption had reached stultifying levels. The technological revolution threatened to leave centrally planned economies permanently behind. And, as columnist John O'Sullivan has noted, "Communism had failed to retain enough true believers who would murder on its behalf."

In East Germany, the party bosses delayed reforms, allowing anger among their own citizens to build until, by 1989, a full 5% of East German adults had taken the risk of being branded disloyal by requesting exit visas. That summer Hungary began allowing East German tourists to slip through to the West, and the genie was out of the bottle. Yet even toward the end the experts thought Marxism-Leninism would stay in place. Many citizens thought so too. "Most Germans themselves are convinced that the prospect of a single Germany is a fantasy," wrote journalist Peter Wyden weeks before the wall fell.

For different reasons, history will record two paramount figures who helped sweep communism into the ash heap of history: Ronald Reagan and Mikhail Gorbachev. Reagan first saw the Berlin Wall in 1978, when he told his aide Peter Hannaford, "We've got to find a way to knock this thing down." After Reagan became president, he returned in 1982 and enraged the Soviets by taking a couple of ceremonial steps across a painted border line. Then, in 1987, he overruled his own State Department by giving the momentous speech in which he implored the general secretary directly to tear down the wall.

Reagan liked to refer in his speeches to the "tide of history," and that idea must have been on Mr. Gorbachev's mind two years later when he visited East Berlin and informed the comrades there that they needed to change. He told reporters who asked about the wall, "Dangers await only those who do not react to life." The signal was sent that Moscow would no longer prop up a corrupt system.

The Berlin Wall's fall was both a vindication of the West's refusal to kowtow to the Soviets and a tribute to the spirit of dissenters behind the Iron Curtain. Today pieces of the wall exist as mere souvenirs on mantelpieces. Sadly, today Russia itself is slipping back into authoritarianism.

It shouldn't surprise anyone that Russia has resisted efforts to erect memorials about the communist era. In 2005, Vladimir Putin, Russia's autocratic president, let slip in a speech that "the collapse of the Soviet Union was the greatest geopolitical catastrophe of the century." Under Mr. Putin's leadership, Russian officials are conspicuously re-creating some of the institutions of oppression. Their frosty silence about three-quarters of a century of communist oppression does not augur well for Russia's future.