How can it be that 70,000 protesters in Leipzig in 1989 tore down the Berlin Wall, while up to a million protesters in Tehran in 2009 managed only – so far – to trigger repression? Or, to phrase it differently, what's the tipping point for revolution? Just when does civil society trump entrenched political power?
Different observers would, of course, give different answers along the spectrum, running from a historian's retrospective determinism to a journalist's fixation on daily blips.
But whatever the viewpoint, the similarities and the differences between Leipzig and Tehran are striking.
In both cases a robust civil society and middle class that habitually guarded their private sphere by eschewing politics suddenly turned political and challenged an authoritarian power structure. In both cases a mobilizing spark was the insult to citizens in apparent official falsification of formal elections that offered little genuine choice anyway. In both cases the social contract snapped; a wide range of businessmen, technocrats, and young mothers spontaneously joined the protest of elite student malcontents.
Furthermore, both framed their demands in religious terms – calling on the moral authority of the Protestant church in then East Germany, chanting "Allahu Akbar" (God is great) nightly in Tehran.
Yet in neither case were the powerful religious or nationalist motives that drive many revolutions a major factor. In Iran both the ruling hierarchy and the demonstrators spoke as Muslims. And nationalism was neutralized as an issue by President Obama's refusal to cheer on the protesters and thus expose them to branding as traitors in service of the Great Satan.
Similarly, in Leipzig, the appeal to East Germany's only autonomous institution – the Protestant Church – was pragmatic rather than devout, and nationalism was negligible. When the chants morphed from "We are the people" to "We are one people," this was no Pan-German chauvinism, but an equally pragmatic move by Leipzigers to lay claim to the same freedom and well-being the West Germans enjoyed.
Despite the similarities, the outcomes in 1989 in Leipzig and 2009 in Tehran were very different. When the Leipzigers on the evening of Oct. 9 ignored their decades-old fear to face down the threat of massed security forces armed with live ammunition and orders to suppress the "counterrevolution," it was the hierarchy that blinked and pulled back the 8,000 police and backups minutes before the unauthorized march started. Four weeks later, this successful defiance nudged the more timid East Berliners to demonstrate; five weeks later, the 28-year-old Berlin Wall fell, without a single casualty. Shortly thereafter, street protesters in Prague, Czechoslovakia; Sofia, Bulgaria; and Timisoara, Romania; ousted their own Communist bosses and gave the death blow to Moscow's external empire. Within less than a year, West and East Germany were reunited. Within two years, the Soviet Union imploded.
By contrast, last month close to a million Iranian demonstrators failed even to pry open the factional fault lines in the ayatollahs' hierarchy and thus expand political participation. Far from chaining the basij militia, the establishment sicced it on the crowds. At least 20 people were killed, hundreds more arrested.
Part of the explanation for this dichotomy can be found in the largest single difference between Leipzig and Tehran: the contexts of 1989 in Europe and 2009 in the Middle East. In 1989 the reforming head of the Soviet Communist Party, Mikhail Gorbachev, had made it clear to his East Berlin dependant, Erich Honecker, that he would not again send Soviet tanks into Berlin to prop him up (as Mr. Gorbachev's predecessor had done for Mr. Honecker's predecessor 36 years earlier).
In 2009, however, Iran's Guardian Council was not answerable to any outsider, nor did it face the kind of existential threat it had come under in the Iran-Iraq war of the 1980s. The council sees Iran as a rising power, one well on the way to restoring its rightful historical hegemony in the region. It chose to lose its electoral legitimacy rather than share power with the street.
Or at least that might be the provisional judgment of both historian and journalist at this point.
And yet it's instructive that the best specialists had no clue beforehand that the East Germans, of all acquiescent people, would erupt in 1989. Or that Iran's vibrant civil society would erupt as soon as this summer over abstract electoral fraud.
Perhaps the moral here is that the only honest answer to the nagging questions about what constitutes a revolutionary tipping point is this: You never really know until after it has already happened.
Elizabeth Pond, a Berlin-based journalist, is the author of "Beyond the Wall: Germany's Road to Unification."