Still others point to the failure of the Moscow coup in August of that year, the occasion of Yeltsin's triumph and Gorbachev's complete failure to understand what had taken place in his country. And some say it coincided with the Kremlin's murderous attacks on the people of Lithuania and Latvia in January 1991.
But perhaps the moment that has the best claim to be the occasion when the Soviet Union died is one that up to now has had fewer advocates. It occurred a year earlier in Baku, when Moscow sought to suppress the Azerbaijanis but unwittingly snapped the fraying bonds of loyalty to the USSR that nation and others as well had felt.
On January 19-20, 1990, a date commemorated this year as every year by the people of Azerbaijan, Soviet security forces went on a rampage in Baku, killing or wounding hundreds of its citizens. While the exact number of victims is disputed, it was almost certainly greater than the total of all other Soviet police actions under Gorbachev.
The Soviet president and his comrades acted not to protect ethnic Armenians as they claimed but rather to punish Azerbaijanis for their increasingly independent stance and to send a message to them and to all the other republics that their Moscow rulers were prepared to do anything, including murder, to hold on to their power.
But the brutality of this act of state terrorism – a Soviet tank ran over the car carrying some senior members of the Azerbaijani Academy of Sciences, and Soviet soldiers shot people at random on the street or even those looking out the windows of their apartments – had exactly the opposite effect that Moscow intended.
In Azerbaijan, the Kremlin's action convinced even those who had doubted it before that they could have no future inside the USSR. Indeed, the day after the killings, many Communist Party members there, including some of its most senior leaders, tore up their party cards; an action that showed there would be now going back.
And elsewhere in the USSR the message Gorbachev and the Soviet leadership hoped to send backfired. Both where many were already seeking independence from Moscow and where few had yet thought about it, Soviet actions in Baku 18 years ago today did not intimidate but rather destroyed the fear that had kept the USSR together.
Besides the need for simple historical accuracy, there are three reasons for people in the region and the world why it is vitally important for everyone in the region and beyond to recognize that January 1990 in Baku was the time and place of the demise of the Soviet Union.
First, given the difficulties and uncertainties of the post-Soviet transitions in many of these countries, some members of the older generation there now view the Soviet past with nostalgia. Having forgotten the evils of that system, they even tell pollsters that the Brezhnev years were "a golden age" when they were secure and their country respected.
Some political leaders across this region even have sought to exploit such attitudes to build their own power either by arguing, as Russia's Vladimir Putin has done, that the end of the USSR was the greatest tragedy in the 20th century, or suggesting that the peoples of this region need Soviet-style stability even at the cost of freedom.
Such leaders naturally do not talk about the violence the Soviet system visited on individuals and groups whose only "crime" was to speak the truth and to entire nations -- be there Kazakhs, Lithuanians or Azerbaijanis -- whose only "deviation" was to want to have the chance to determine their own destinies.
Recalling to these people what happened at Baku 18 years ago today is thus important as a powerful antidote to any who have so forgotten what the Soviet system was like that they would support its full or partial return.
Second, with each passing year, the share of the population in the post-Soviet states who lived under and were shaped by the communist regime is declining, and in many places, it is falling fast. Few under the age of 40 today were formed by the communist regime, and none at all of those who are now under the age of 30.
Because these younger people do not have immediate memories of what Soviet rule meant, they frequently have a distorted or at least incomplete view of what it was about and thus are available for mobilization by unscrupulous politicians who play up what they say were the "glories" of that system while saying nothing about its costs.
The danger that young people, who should be the hope of the future, might help power a return to that past is so great that one Belarusian paper this week went out of its way to explain to the generation which never knew the USSR why no one should want its return (http://www.gazetaby.com/index.....
The Soviet Union, "Salidarnasts'" wrote, began its life as "an unbridled, cruel and clever monster" but ended as "a powerless, malicious and pathetic figure," capable of massive but senseless violence against its own people and others, yet incapable of giving anyone freedom, dignity, or a better life.
That system "would have been 85 years old on December 30th" of last year, the Belarusian paper observed, "But happily the USSR did not survive to that date." One of the reasons it did not is that despite its outwardly impressive coercive powers, its people – again be they Balts, Belarusians or the residents of Baku – no longer respected it.
Having failed to provide any basis for loyalty other than fear, the Soviet Union was swept away into the dustbin of history it was always threatening to send others to when people there demonstrated that they were no longer afraid and that for them, Moscow's period use of violence simply underscored the weakness of the system.
Informing this younger generation whose members never lived under communism about how that tectonic shift occurred in the Azerbaijani capital 18 years ago today thus can help immunize them against the duplicitous claims of those who distort the history of the Soviet past for their own purposes.
And third, many far beyond the borders of what was the Soviet Union need to learn in detail what happened in Baku and why the events there played such a critical role in the demise of the USSR so that they will be able to escape the still-widespread myths about just what happened here.
On the one hand, because so few people in the West in 1990 looked beyond Moscow except to those republics with large and active co-ethnic communities in the West, many analysts there continue to exaggerate the role of the Russians and those with such ties in the demise of the Soviet Union while minimizing the contributions of others.
To say this is in no way to play down the contributions that the Russians and these others made to the demise of the Soviet system both by calling attention to other crimes and by their struggling against the system. These were enormous. But both historical justice and the possibility of a better future requires a more comprehensive picture.
And on the other, because so many people in the West then and now view predominantly Muslim countries like Azerbaijan only through the prism of their conflicts with non-Muslims and as the objects of history rather than its subjects, they are unprepared to acknowledge the independent importance of what happens in these states.
The continuing failure of many in Western countries to do so reinforces a highly selective, culturally myopic view of the historical record. And far more seriously, it undermines the chances that Western countries and the peoples of these countries have to work together.
Reminding those in the West who have a less than comprehensive view about what happened in Baku 18 years ago today and the role that the people of Azerbaijan played in the death of the Soviet Union thus can ensure that they will be better prepared to help create a future in which tragedies like Black January will never happen again.