First came Mikhail Gorbachev, who moved a monolithic Soviet Union toward reform. Then in August 1991, an ill-conceived coup attempt by clumsy and occasionally drunken men opened a crack that could not be closed.
A few pieces of the empire fell off and floated away. Soon the rest of the mass collapsed.
Triumphalists in the West saw the USSR's disintegration as the inevitable triumph of democracy, even as "the end of history." Others, as Russian leader Vladimir Putin, later put it, bemoaned the "greatest geopolitical catastrophe of the century."
The shards of the Soviet Union lie somewhere between those extremes _ a jumbled pile of countries, totaling one-sixth of the world's land mass, that are wildly different from each other and facing futures ranging from promising to troubling to anyone's guess. Islamic insurgencies threaten to explode into wide fighting, and two "frozen conflicts" appear nowhere near resolution.
They range from Europe's poorest nation, Moldova, to Russia, which breeds tycoons of Pharaonic wealth. Some are genuine democracies; others are unconvincing, or cynical, imitations; Turkmenistan is an open dictatorship and Belarus and Uzbekistan effectively are the same. In the assessment of the Freedom House watchdog group, three of the 15 former Soviet republics are considered free, seven not free and the other five somewhere in between.
Russia is among the "not free," losing ground over the past decade. By far the largest former Soviet republic, the one with the most lavish treasure chest of natural resources and the only one to still have nuclear weapons, the path that Russia chooses is of key concern to the world _ and the path is far from clear.
In the first years after the Soviet Union's collapse, Russia's political scene seemed wide open, as reformers, opportunists and rabid nationalists entered the arena. In 1996, the presidential election competition was so intense that it forced a second round of voting, which Boris Yeltsin won with only 53 percent of the vote.
But Putin's Russia, though nominally a democracy, has clamped a tight lid on any genuine opposition politics, except for the increasingly marginal Communist Party. Authorities routinely deny opposition groups permission to rally and police harshly break up unauthorized gatherings; election-law changes over the past decade threw up almost-insurmountable obstacles to independents and true opposition groups.
President Dmitry Medvedev has repeatedly spoken of the need for reform, but as a weak president who attained office only because Putin could not run for another presidential term in 2008, his words have had little impact. Putin, currently prime minister, is widely expected to run for the presidency next year and would be certain to win. That would reinforce the so-called "managed democracy" system, which many observers believe could lead to catastrophe.
"Russia throughout its history repeatedly saw political reforms launched only when it was already too late. And now the nation is again heading in the same direction," said Boris Makarenko of the independent Moscow-based Center for Political Technologies. "The government can't endlessly ignore society's opinion. If they attempt to do that, it could lead to the scenarios of 1917 or 1991."
Russia's recent stability and its citizens' willingness to accept declining political freedoms are closely tied to the astonishing wealth that has flowered in the country since the Soviet collapse, hinging on world demand for its vast supplies of oil and natural gas. Even Russians who can't afford the multimillion-dollar apartments of central Moscow appear excited by watching from the sidelines.
But the global economic crises of 2008 and 2011 starkly illustrated how vulnerable Russia is to drops in hydrocarbon prices. Prolonged economic stagnation or decline could rock the political system.
"Without growth, it would be difficult for the government to 'buy off' discontent," University of California at Los Angeles professor Daniel Treisman said in a paper for the Carnegie Moscow Center.
Russia also is plagued by an Islamic insurgency in its Caucasus provinces, an offshoot of the two post-Soviet wars with Chechen separatists. The violence periodically spreads deep into the heartland, as in January when a suicide bomber killed 36 people at Moscow's largest airport.
Kazakhstan, smaller than Russia but still larger than all of Europe, has also thrived on its gas reserves and other natural resources. And its prospects for democracy are even more doubtful than Russia's. Nursultan Nazarbayev, who has led the country since the Soviet collapse, holds unchallenged power and his party occupies every seat in the national legislature. Yet Nazarbayev strikes a more progressive posture than have Russia's leaders, eagerly giving up the nuclear weapons that Kazakhstan inherited from the Soviet Union and promoting ethnic and religious tolerance.
However, neighboring Kyrgyzstan remains a focus of worry because of violent animosity between ethnic groups, which exploded last year in pogroms in the south that killed hundreds. Both the United States and Russia have air bases in the country and stability there is a key concern for both Moscow and Washington.
Kyrgyzstan's moment of truth may come in national elections in October, showing whether the country can return to the democratic path it bloodily veered away from in recent years. Once regarded as the region's "island of democracy," Kyrgyzstan since 2005 plunged into two violent overthrows of power.
Two other former Soviet states' moves toward democracy and the West deteriorated but have not definitively collapsed.
Ukraine, where massive protests in 2004 ushered in a reformist Western-leaning pro-NATO government, almost immediately devolved into factional jealousies that effectively paralyzed the country. Voters threw out that regime last year in favor of a Russia-friendly president, who is under wide criticism from the West for politically motivated prosecutions and pressure on independent news media. Ukraine meanwhile has acquired international notoriety for frequent brawls in parliament, and whether the country ultimately tilts West or East remains a question.
Georgia, whose 2003 "Rose Revolution" led the way for the region's regime-changing mass protests, was driving firmly toward NATO and European Union membership under reformist President Mikhail Saakashvili. But the momentum petered out after Georgia's five-day war with Russia in 2008, which both the Kremlin and many Georgians blame on Saakashvili's impetuosity.
The two Georgian regions that split off in the war, South Ossetia and Abkhazia, remain potential flashpoints, with Georgia alleging they are occupied territory used as staging points for Russian terrorist incursions.
Not far from Georgia lies another obdurate problem _ Nagorno-Karabakh. This Luxembourg-sized territory, deep inside Azerbaijan, has been controlled by Armenian soldiers and ethnic Armenian forces since a 1994 cease-fire ended separatist fighting. More than a decade of international mediation has brought no apparent move toward resolution, and both sides frequently report small clashes across the no-man's-land that separates them. A renewal of full-scale fighting could shake European markets because of the key oil pipeline that passes through Azerbaijan en route to the West.
Less volatile, but equally stagnant, is the status of Transdniester, a separatist sliver of Moldova reinforced by Russian troops.
At one extreme of the post-Soviet experience lie Estonia, Latvia and Lithuania. The first to leave when the USSR was disintegrating, these three small countries have taken a firmly Westward course, all joining NATO and the EU.
At the other stand authoritarian Uzbekistan, Belarus and Turkmenistan. No change appears even remotely likely in Uzbekistan until strongman leader Islam Karimov leaves office. Belarus' President Alexander Lukashenko, who has suppressed opposition and independent media, currently faces the biggest threats to his 17-year rule as the Soviet-style command economy collapses.
Turkmenistan, where huge natural gas revenues have transformed the once-dismal capital into a shiny desert showpiece resembling Las Vegas, has thrown off much of the personality cult engendered by the late eccentric leader Saparmurat Niyazov, who had banned gold teeth and ballet, but it remains a single-party state. However, Niyazov's successor has invited exiled opposition leaders to return to take part in next year's elections in what may be a hesitant step toward openness.
The differing fates and prospects of the countries add up to a historical irony: Whereas the Soviet Union sought to spread a single ideology throughout the world, its former territory is now as varied as the world itself.
Associated Press writer Vladimir Isachenov in Moscow contributed to this story.