Former Soviet president Mikhail Gorbachev. Credit:AP Putin and Trump have both since called for stronger nuclear weapons in their countries. Now Gorbachev, 85, is back in the news - this time warning of possible global war. "The world today is overwhelmed with problems," he wrote in the first line of an essay in Time magazine. "Policymakers seem to be confused and at a loss." He listed some problems: "the militarisation of politics and the new arms race", bellicose world leaders and a media that echoes them. Tanks and weapons in Europe "placed closer to each other, as if to shoot point-blank".

Then US President Ronald Reagan and Soviet leader Mikhail Gorbachev exchange copies of a treaty to eliminate intermediate-range missiles during a signing ceremony at the White House on December 8, 1987. Credit:AP "It all looks as if the world is preparing for war," Gorbachev wrote. His tone had darkened since his song in December - if not since the Soviet Union dissolved beneath his feet a quarter century ago. But Gorbachev's advice for the world was much the same: do as he and former US president Ronald Reagan, whose co-operation and mutual disarmament may well have averted World War III, did. Gorbachev's essay summarises the lurching end of the Cold War in a few brief lines: "In the second half of the 1980s, together with the US, we launched a process of reducing nuclear weapons and lowering the nuclear threat."

The reality wasn't so neat, though it seemed impossibly rapid to a world that had spent a century under the cloud of global war. Gorbachev took over the Communist Party in 1985, as Reagan was beginning his second term in the White House with pushes for a new nuclear missile and a more robust military. Many Americans credit Reagan's hard line on military policy - such as his push for missile defence - with forcing the Soviet Union to reform and eventually collapse. In his own interviews, Gorbachev has spun history differently. "Our interests coincided," he told The Washington Post in 2004, after giving Reagan's coffin a fond pat at his funeral.

"We both knew what kind of weapons we each had," he said. "There were mountains of nuclear weapons. A war could start not because of a political decision, but just because of some technical failure." Whatever inspired him, Gorbachev is remembered for softening a totalitarian empire - making the Soviet Union more open and liberal while cutting its nuclear stockpiles, as Reagan reciprocated. The push for world peace was distilled in Reagan's famous call in 1987 - "Mr Gorbachev, tear down this wall!" - followed two years later by the border opening between East and West Germany, and the destruction of the Berlin Wall. Gorbachev would later complain that the peacemaking got out of hand after his rivals took advantage to oust him in a coup d'etat, which led to his resignation on the same day the Soviet flag fell at the Kremlin. Now, as he sees signs of peace undone across the world, he is calling on the Kremlin and White House's new occupants to join forces again and stop it.

In Time, Gorbachev urges "the presidents of two nations that hold over 90 per cent of the world's nuclear arsenals" to push for a United Nations resolution condemning nuclear war. But neither Trump nor Putin sound like they want his advice. "The United States must greatly strengthen and expand its nuclear capability," Trump wrote in a tweet on December 22 - the week of the anniversary of Gorbachev's resignation. Loading The same day, Putin praised his country's military operations in Syria. He joined Trump in calling for a stronger arsenal - more nukes, not less.

The Washington Post