In 1975, physicist Andrei Sakharov and a group of fellow Soviet academicians warned the Kremlin leadership that unless the nation’s ruinous defense spending was slashed and funds refocused on modernizing the nation’s decrepit, obsolete industrial base and its wretched state agriculture, the Soviet Union would collapse by 1990.

Their grim warning was prescient. Twenty years ago this week – 9 November, 1989 – boisterous German crowds forced open the hated Berlin Wall, Communist East Germany collapsed in black farce, and the once mighty Soviet Empire began to crumble.

This was one of modern history’s most dramatic and dangerous moments. No one knew if the dying Soviet Union would expire peacefully, or ignite World War III.

In November, 1989, the vast empire built by Stalin that stretched from East Berlin to Vladivostok was on its last legs. The USSR had 50,000 battle tanks and 30,000 nuclear warheads, but could not feed its people. Military spending consumed 20% of the economy. As I saw for myself while traveling around the Soviet Union in the late 1980’s, conditions were often primitive, even third world outside the big cities.

Afghanistan’s "mujahidin" had all but defeated the mighty Red Army. Poland’s Solidarity Union, secretly funded by Pope John Paul and the CIA through Panamanian shell companies, had risen in revolt. So, too, ever rebellious Hungarians, joined by Lithuanians and East Germans.

The old joke in Moscow was that the East Germans were the only people who could make Communism work. Now they were in revolt.

The reformist Soviet president Mikhail Gorbachev had to make a fateful decision: allow events to take their course, or order the Red Army and KGB to crush the spreading uprisings – and run the risk of war with NATO, particularly so if the Warsaw Pact’s armies turned their guns against the Soviet occupation forces and fighting spread across the Inner German Border.

Unlike his brutal Soviet predecessors, Mikhail Gorbachev was a man of profound moral values, a genuine humanist and idealist who believed he could reform the USSR through democratic socialism and patient, open debate – his "glasnost and perestroika."

After a violent incident staged by Communist hard-liners in the Baltic, President Gorbachev refused to use force against his own people.

But once fear of repression was removed, the Soviet Union, a nation of 120 languages spread over eleven time zones, shattered. Gorbachev simply could not control the ensuing whirlwind of nationalism his reforms had sown.

Today, most Russians revile Gorbachev for wrecking the Soviet Union. The sinister Communist era, including Stalin’s monstrous crimes, are being sugarcoated with nostalgia.

Russia’s Prime Minister, Vladimir Putin, called the collapse of the Soviet Union "the greatest tragedy of the 20^th century."

In truth, the Soviet Union was history’s most brutal, murderous tyranny that killed three times more victims than Hitler.

Gorbachev did not plan to destroy the Soviet Union but to reform and revitalize it. But by refusing to hold it together by force, he brought about its doom.

Gorbachev did the world a huge favor.

In any event, the Soviet Union was destined to crumble, Gorby or no Gorby. Like the old Ottoman Empire, the USSR could only survive by gobbling up its neighbors.

In 1989, the state that had run on virtual war footing since 1945, died of exhaustion. As Voltaire said of Prussia, the Soviet Union was an army, disguised as a state.

For me, Gorbachev was one of the greatest men of our time. He put international law, basic humanity, and civilized behavior before the demands of brute power. We must also salute Gorbachev’s chief lieutenant and powerhouse behind the reform movement, former Georgian KGB chief and Soviet Foreign Minister, Eduard Schevardnadze, who urged total de-communization and disarmament.

Later, as president of independent Georgia, Shevardnadze was overthrown – ironically – by a US-organized revolution.

Gorbachev purged hardeners from the Soviet military-industrial complex, vetoed an antimissile system, sharply downsized the Soviet military, and wisely ended the Soviet occupation of Afghanistan, a lesson Nobel Peace Prize Winner Barack Obama has yet to learn.

But when Gorbachev and Shevardnadze sensibly sought total nuclear disarmament, President Ronald Reagan, obsessed by the unworkable Star Wars antimissile project, refused Russia’s offer that would have eliminated all nuclear weapons and missiles.

Other courageous Russians reformers who helped end the Cold War deserve to be remembered: Anatoly Chernayev; Georgi Shakhnazarov; former ambassador to Canada, Alexander Yakovlev; and Gorbachev’s brave, cerebral wife and confidante, Raisa.

Germany’s Chancellor Helmut Kohl and President H.W. Bush also merit kudos for their able management of the Cold war’s end. By contrast, Britain’s Margaret Thatcher shamefully relapsed into Europe’s evil old ways by trying to block German unification.

President Gorbachev kept begging the western powers to launch another Marshall Plan to rescue the dying Soviet Union and democratize it. Tragically, they did not. Instead, the Clinton administration chose to treat the new, battered Russia as a client state.

Communist die-hards launched a farcical, drunken coup against Gorbachev that was thwarted by the courage of the then still sober Russian president, Boris Yeltsin; Aviation Marshall Yevgeny Shaposhnikov; and – a story that is still little known in the west – KGB moderates.

In 1990, I was the first western journalist ever allowed into the dreaded Lubyanka Prison, the headquarters of KGB, to interview senior KGB officers of the elite First Directorate (from whence came Vlad Putin) who had turned against the Communist Party and were seeking to reform Russia.

In the end, Gorbachev was left the leader of a nation that had ceased to exist, the USSR, the object of popular wrath, a great statesman without a country, a Russian King Lear on a blasted heath.

Twenty years later, the world owes Gorbachev an enormous debt of gratitude for ending the Cold War, and freeing Eastern Europe and the Baltic states. Thank our lucky stars Gorbachev was in power when the Soviet Union met its inevitable collapse – or we could have faced World War III.

Mikhail Sergeyevitch Gorbachev showed that once in a millennium a great political leader can rise above the law of the jungle.