DONALD Trump has threatened to tear up the United States’s 1987 nuclear weapons treaty with Russia, an agreement that bans intermediate-range nuclear systems. Put simply, these are first-strike weapons designed to knock out the other side’s command and control capability. Sited close to the enemy, they can kill before retaliation is possible. Just deploying them is utterly destabilising because it vastly reduces the timeframe in which political and military decisions are made.

To be sure, Putin has stretched the treaty rules by announcing the development of supersonic cruise missiles and by deploying mobile Iskander-M missile launchers – capable of firing either conventional or nuclear warheads over a range of 500km – to Kaliningrad on the Baltic. However, in this new nuclear arms race, the US has made all the first moves.

In 2002, George W Bush withdrew the US from the Antiballistic Missile Treaty (ABM) with the old Soviet Union. Bush wanted a new generation of rockets capable of downing rogue North Korean and Iranian missiles. But he also wanted to send a message to post-communist China and Russia. Barack Obama followed this up by authorising the deployment of the new Aegis anti-missile shield in Romania and Poland – a direct challenge to the Kremlin rather than Tehran.

The reason for the original 1972 ABM treaty restricting anti-missile missiles is that if you can kill your opponent’s retaliatory rockets, you might be tempted to launch a first strike. The treaty put that temptation out of harm’s way. Putin’s recent obsession with acquiring intermediate missiles is actually a response to America’s plan to surround itself with a missile defence shield.

Why has Trump announced that he plans to end the treaty? Partly as a stunt just before the US mid-term elections. Partly to draw media attention away from his support for Saudi Arabia in the brutal assassination of Jamal Khashoggi. And because he wants to clear the decks for America’s own, long-planned expansion of first-strike nuclear weapons, while pinning the blame on Russia.

First, the US is deploying a new generation of low-yield, tactical nuclear bombs for battlefield use. This blurs the line between nuclear and conventional warfare, making an accidental, large-scale atomic exchange a horrible possibility – especially given Trump’s reckless personality. Last year, the US Air Force also awarded big contracts to Lockheed Martin and Raytheon to develop a long-range, supersonic cruise missile. Delivered by stealth bombers, these would be capable of overwhelming enemy defences in a first strike.

The world’s attention has been focused on the efforts of North Korea and Iran to acquire nuclear capability. In truth, these are minor powers with only nuisance value. US, Japanese and Israeli anti-missile defences can easily overwhelm rogue attacks. The actual danger to human survival is America’s economic and military rivalry with China. US threats to Russia (an economic minnow these days) serve as a proxy to remind Beijing of the US’s determination to remain global hegemon. Some misguided souls blame this massive destabilisation of the global order on the personality of Donald Trump. Such optimists hope the world will revert to “normal” once he retires. Not so. The president is only the immediate personification of a permanent shift in the international economic and political system. Essentially, we are seeing the permanent breakdown of the rules-based system that governed the globe after the Second World War, under American overlordship.

The basis of this system lay in two developments. First, the great European imperialisms lay prostrated, ruined and exhausted in 1945 while US capitalism had emerged from the conflict rich and politically supreme. America used its new position to force the European powers to accept US leadership in the Cold War against Stalin’s Russia and Mao’s China – and to de-colonialise.

Franco-German imperialism recognised this arrangement, partly to buy time to rebuild their shattered economic bases; and partly because a weakened Europe needed US protection against the supposed Communist threat. From this set of alliances were born the EU, Nato and a set of international economic institutions (IMF, World Bank and WTO) that ended protectionism, forcing open the global market to US capital and multinationals.

The second element in the new global order was the survival and expansion after the Second World War of Stalinism, now spread to China and eastern Europe.

In fact, despite the conflicts in Korea and Vietnam, the leaders of the Communist bloc were deeply conservative and had no real desire to export revolution to the West – a move that would have risked mutual annihilation. Besides, the sclerotic economies of the Eastern dictatorships proved no match for the ability of Western capitalism to churn out consumer durables. For most of the Cold War, communist East and capitalist West growled at each other in public, but privately agreed not to interfere with each other’s sphere of interest. Thus

“co-existence” was born – a system in which both sides ensured stability in their respective zones with utter ruthlessness.

Only the accidental Cuban Missile Crisis threatened to unleash nuclear Armageddon, after which both sides determined to preserve their global truce in aspic. As a result, come the 1980s, Ronald Reagan and Margaret Thatcher were happy to “do business” with Mikhail Gorbachev, signing the various nuclear disarmament treaties and scrapping first-strike weapons.

Of course, the post-war era may rightly be characterised as a period of grand cynicism. Nor was it quite as stable as it appears. Popular protest broke out repeatedly – in Europe in the 1960s, in the colonial world, and behind the Iron Curtain (in Hungary, Poland and Czechoslovakia). The Cold War atomic stalemate was always precarious, prompting the CND disarmament movement and mass protests across Europe in the 1980s against the initial deployment of first-strike weapons – the real author of the intermediate-range rocket ban.

Where are we now? US economic and political hegemony has been undermined by the rise of Chinese capitalism and a rejuvenated Europe, with both hiding behind new protectionist barriers. Paradoxically, the end of Stalinism has expanded capitalism at the expense of a massive increase in economic competition, with a resulting destabilisation of the world order. Trump’s trade wars are the political manifestation of that competition. The nuclear arms build-up is its ultimate expression.

We desperately need a new, popular peace movement to oppose the deployment of first-strike weapons. But the collapse of a rules-based global order demands more: a total rethink in foreign policy, especially for an independent Scotland. The SNP may need to revisit the idea of joining a “first strike” Nato.

Any thought of the SNP hosting Nato nuclear bases post-independence – even for a transitional period, as is being rumoured – must be resisted. Post Trump, post-Xi, and post-Putin, we need to create a new, non-aligned international bloc to combat the slide into war. And do so urgently.