It renamed itself the Party of Democratic Socialism (PDS), salvaged many of its assets (in ways that critics have called criminal) and emerged soon enough as a kind of regional protest party for the discontents of unification.
His party more than doubled its seats in the Irish parliament, and has used its new prominence to launch yet another campaign for Irish unification.
Russia's own role in fixing the terms of German unification was now erased from memory, replaced by a mythical sequence of unmediated aggressions whose ultimate purpose was to justify current Russian policy in the Ukraine.
In April 2009, Mikhail Gorbachev expressed his outrage at the way Russia had been hoodwinked by the west in the years following German unification in 1990.
In a landmark speech at the Munich security conference last month the Russian foreign minister, Sergei Lavrov, cast doubt on the legitimacy of German unification, proposing – to the baffled amusement of his audience – that it was less "legal" than the "reunification" of the Crimea with Russia.
Notwithstanding our differences of opinion, which remain, we worked closely and fruitfully together to advance the important processes of that time – curbing the arms race, European developments, German unification and reversing Iraq's aggression in the Middle East.
After unification the former "leading party" of East Germany, the Socialist Unity Party of Germany, narrowly escaped complete destruction.
Fear of the domino effect of the uprisings prompted Abdullah to seek Gulf unity, but resistance from Qatar and Oman put the unification project on hold.
Even if Dodds doesn't get his way in reducing the number of north-south bodies to drive down state spending, the fact that all of McGuinness and Robinson's plans are contingent on what Alistair Darling says still undermines the thesis that the devolved institutions are ante chambers leading towards Irish unification.
The South's unification ministry described the response as regrettable but said the offer would remain on the table.
But the memory of Nato's broken promises also matters because it touches on the legitimacy, in Russian eyes, of the international settlement established during the German unification process and the European order that emerged in its wake.
