Mikhail Gorbachev, who ended the Cold War without bloodshed but failed to prevent the collapse of the Soviet Union, has died at the age of 91.
Gorbachev, the last Soviet president, forged arms reduction deals with the United States and partnerships with Western powers to remove the Iron Curtain that had divided Europe since World War 2 and bring about the reunification of Germany.
But his broad internal reforms helped weaken the Soviet Union to the point where it fell apart - a moment that President Vladimir Putin has called the "greatest geopolitical catastrophe" of the twentieth century.
"Mikhail Gorbachev passed away tonight after a serious and protracted disease," Russia's Central Clinical Hospital said on Tuesday.
He will be buried in Moscow's Novodevichy Cemetery next to his wife Raisa, who died in 1999, said Tass news agency, citing the foundation that the former Soviet leader set up once he left office.
Putin expressed "his deepest condolences", Kremlin spokesman Dmitry Peskov told Interfax news agency. "Tomorrow he will send a telegram of condolences to his family and friends," he said.
Putin said in 2018 he would reverse the collapse of the Soviet Union if he could, news agencies reported at the time.
World leaders were quick to pay tribute. European Commission chief Ursula von der Leyen said Gorbachev had opened the way for a free Europe.
British Prime Minister Boris Johnson, citing Putin's invasion of Ukraine, said Gorbachev's "tireless commitment to opening up Soviet society remains an example to us all".
"Gorbachev died in a symbolic way when his life's work, freedom, was effectively destroyed by Putin," said Andrei Kolesnikov, senior fellow at the Carnegie Endowment for International Peace.
When pro-democracy protests swept across the Soviet bloc nations of communist Eastern Europe in 1989, Gorbachev refrained from using force - unlike previous Kremlin leaders who had sent tanks to crush uprisings in Hungary in 1956 and Czechoslovakia in 1968.
But the protests fuelled aspirations for autonomy in the 15 republics of the Soviet Union, which disintegrated over the next two years in chaotic fashion. Gorbachev struggled in vain to prevent that collapse.
"The era of Gorbachev is the era of perestroika, the era of hope, the era of our entry into a missile-free world ... but there was one miscalculation: we did not know our country well," said Vladimir Shevchenko, who headed Gorbachev's protocol office when he was Soviet leader.
"Our union fell apart, that was a tragedy and his tragedy," RIA news agency cited him as saying.
On becoming general secretary of the Soviet Communist Party in 1985, aged just 54, he had set out to revitalise the system by introducing limited political and economic freedoms, but his reforms spun out of control.
His policy of 'glasnost' - free speech - allowed previously unthinkable criticism of the party and the state, but also emboldened nationalists who began to press for independence in the Baltic republics of Latvia, Lithuania, Estonia and elsewhere.
Many Russians never forgave Gorbachev for the turbulence that his reforms unleashed, considering the subsequent plunge in their living standards too high a price to pay for democracy.
After visiting Gorbachev in hospital on June 30, liberal economist Ruslan Grinberg told the armed forces news outlet Zvezda: "He gave us all freedom - but we don't know what to do with it."
Flawed reformer on an impossible mission
For all the adulation he inspired in the West, Gorbachev was a tragic figure who failed in the historic mission he had defined for his own country.
The award of the 1990 Nobel Peace Prize marked the pinnacle of world acclaim for the role that Gorbachev had played in ending the Cold War without bloodshed.
But at home he was a drained and defeated man when forced to step down the following year, reduced to leader of a non-existent country as the Union of Soviet Socialist Republics collapsed into 15 separate states.
Gorbachev had set out to revitalise the moribund Communist system and shape a new union based on a more equal partnership between the 15 republics, of which the two most powerful were Russia and Ukraine. Yet in the space of six years, both Communism and the Union came crashing down.
With hindsight, some of his mistakes are clear to see.
He attempted political and economic reforms simultaneously and on too ambitious a scale, unleashing forces he could not control. It was a lesson not lost on China's leaders, who embraced the market economy but served notice with the 1989 killings of protesters on Tiananmen Square that they would act ruthlessly to defend the Communist Party's grip on power.
Gorbachev never stood for election to earn himself a popular mandate - unlike his great rival Boris Yeltsin, who was voted into power as president of Russia and was instrumental in the dissolution of the USSR and the ousting of Gorbachev.
And he failed to anticipate the strength of nationalist feeling - initially in the Baltic republics of Latvia, Lithuania and Estonia, and spreading to others like Georgia and Ukraine - that would create unstoppable momentum to escape Moscow's grip.
"He didn't believe that the Soviet Union was actually an empire in itself of nations that did not want to be shackled," said Jonathan Eyal of the Royal United Services Institute, a think-tank based in London.
"Like all Soviet leaders, and dare I say like Russian leaders today, he saw the Soviet Union as synonymous with Russia and he simply could not understand why nations wanted to be independent."
'Seed of his downfall'
Some historians believe Gorbachev was right to conclude from the start that the system he inherited was falling further and further behind the West and nothing short of bold reform could save it. Others take a more critical view.
"I think the seed of his downfall was that essentially he didn't really understand the Soviet Union, Soviet society and how it worked," said Alexander Titov, lecturer in history at Queen's University Belfast.
"He thought it could be reformed, he thought removing some of the essential elements of the Soviet system such as the fear, the repression, the command economy and so forth would still preserve the system. But they turned out to be the actual essential elements of the Soviet system - having removed them, the system unravelled as well."
In the three decades since his fall from power, Russia has judged Gorbachev harshly. When he ran for Russian president against Yeltsin in 1996, he trailed home in a humiliating seventh place with 0.5% of the vote.
Russians have long been accustomed to viewing him as a weak leader who was duped by the West.
Many still blame him for the collapse of the Soviet Union - which President Vladimir Putin famously called the greatest geopolitical catastrophe of the 20th century - and the years of economic upheaval and political turmoil that followed, including wars from the Caucasus to Chechnya and Central Asia.
Putin's lurch into confrontation with the West and his invasion of Ukraine have destroyed the Gorbachev legacy of detente with the West and nuclear arms agreements with the United States. With Putin pointedly boasting of the size and destructive power of Russia's arsenal, politicians in both Moscow and Washington have evoked the risk of World War 3.
The man now in power in the Kremlin has also smashed the idea embodied by Gorbachev that Russia could retreat from empire and still remain a major power, said Eyal.
"The imperial aspiration is now reasserted as the official policy in Moscow and the general approach - that what you need to do if you face a crisis is to crush it with tanks - is now back in fashion," he said.
"It's one of the ultimate tragedies of (Gorbachev) that none of the points that he ultimately came to accept and espouse have been preserved by the leaders of Russia today."
