Nations in and near Eastern Europe have long feared the sort of brutal onslaught Russia’s Vladimir Putin is visiting upon Ukraine.

That fear is heightened by the horrifying prospect that if, against the odds, they manage to bring the Russians to the point of defeat, Putin will launch a ‘battlefield’ or ‘tactical’ nuclear weapon to destroy them or their NATO allies.

That will be exercising the minds of Polish leaders conscious that their nation is a vital supply route to its beleaguered neighbour which is using weapons supplied by allies to inflict undreamed-of damage on the Russian invaders.

In 2016, I attended a military exercise in Poland involving 31,000 troops from the United States and other NATO countries along with nations that were once members of the Warsaw Pact. On a vast stretch of rolling meadow scattered with trees in northern Poland, a combined team of US Apache attack helicopters and Soviet-era Hind gunships blasted a ‘Red’ army force trapped in a valley below.

No one on the ‘Blue’ army side, or among the watching politicians and NATO officials, acknow­ledged that the ‘Red’ force that had been cut off after invading from the north represented the Russians—but that’s clearly who it was.

The exercise was driven by rising fears of Putin’s Russia and its willingness to use force to threaten, weaken and ultimately invade weaker nations on its borders. This included regular reminders from Moscow that it had a nuclear arsenal.

By 2016, Russia wasn’t ‘red’ anymore, but a succession of events in Europe had breathed new life into a Cold War most of the world thought was long dead.

In 2014, Russia’s neighbours were appalled by its forced annexation of the Crimean peninsula which had been part of Ukraine. After that success, Russia infiltrated thousands of its regular troops, the so-called ‘little green men’, into Ukraine’s Donbas region until the war there reached a stalemate.

By then, Putin’s bullyboy tactics, his threats and his unpredictability had his country’s former allies, and the rest of Europe, badly spooked. Russia said it was merely reacting to NATO’s expansion eastwards and the installation of missile defence systems across nations that once were part of the Soviet bloc. Having a protective moat of acquiescent nations had long provided Moscow with a measure of comfort.

To achieve what it wanted in Eastern Europe, Moscow engaged in a multifaceted strategy some in the West tagged ‘hybrid warfare’. That worked best in countries on Russia’s borders where there was already some political instability or ethnic tension.

Russia builds up opposition to the status quo, ideally by working with members of an ethnic Russian minority, triggering demonstrations and targeting people such as journalists who raise the alarm to put them out of work by damaging their reputations and swamping their email systems to shut them down.

When the situation is destabilised, regular Russian troops can be sent to train and stiffen violent opposition groups and destabilise, disorientate and weaken the country. The next step is to make the opponent look like the aggressor so there’s an excuse to send in forces who look as if they are defending legitimate interests.

London’s Chatham House says this type of hybrid warfare is not new or substantially different from past Russian and Soviet doctrine. It’s just the Russian way of achieving its policy objectives and waging war using a range of weapons, some of them non-military.

The 2016 Exercise Anakonda led by Poland was designed to demonstrate to Moscow that the US and Western and central European nations were willing to come to the aid of one-time Russian satellite nations monstered by the Kremlin.

With them were forces from non-NATO nations Sweden and Finland. Poland, Lithuania, Latvia and ­Estonia, on the ­alliance’s vulnerable eastern flank, were former members of the Warsaw Pact that joined NATO after the collapse of the ­Soviet Union. All of these nations are now watching events in Ukraine with horror and disbelief. But they are also playing a part in supporting the Ukrainian government and forces with weapons to use in their defence. These newer NATO members have turned out to have influential voices in shaping the re-energised NATO we are starting to see.

Putin’s use of language is as chilling as his approach to nuclear weapons and is also an echo of past Russian doctrine and policy. As part of a ‘de-escalation strategy’ in the event of a conflict, Russian military chiefs could order the use of a relatively small and low-yield nuclear bomb fired by artillery or launched on a missile.

The intention would be to leave the NATO nations that have nuclear weapons—the US, Britain and France—with the unspeakable choice of using a similar bomb against Russian forces and embarking on a nuclear war or pulling back their forces to avoid possible annihilation.

Polish officials said in 2016 that even if Russia didn’t carry out such a threat, leaving the very possibility dangling was a weapon in its own right designed to create fear and uncertainty among allied ­nations and weaken their resolve to act.

Poland’s then defence minister, Antoni Macierewicz, said that he was less worried about the threat from Russia because his nation was assured of support from other NATO countries. Addressing a future that looked much like the current Russian war against Ukraine, Macierewicz told me that if a neighbour such as Ukraine were threatened by Russia, Poland would keep its promise to help ‘restore its territorial integrity’.

At the time, concerns focused on the area known as the Suwalki Gap along ­Poland’s border with Lithuania. This is the 100-kilometre-long strip of land between the Russian exclave of Kaliningrad and close Russian ally Belarus. Polish military leaders feared that if NATO forces advanced into Lithuania through that gap to help one of the Baltic nations, Russia could set off a nuclear blast to stop or discourage the allied advance.

As Russia continues to attack Ukraine’s cities with bombs, shells and missiles, its long military convoy on the road to Kyiv would make an enticing target for allied air forces.

Putin has shown off his army in action and, apart from what it’s done to Ukraine’s cities, NATO commanders must be wondering why they feared the Soviet and Russian conventional forces for seven decades—although those forces have demonstrated their traditional willingness to unleash massive firepower on ‘soft’ targets.

Some of the Russian troops have been so lacking in education, training or any sense of self-preservation that they used a tank to fire on a Ukrainian nuclear power plant, setting sections of it on fire.

With poor-quality tyres unable to deal with boggy ground, the formidable looking Russian troop transports and rocket launchers have had trouble crossing terrain that could be traversed by enthusiasts from any serious four-wheel-drive club.

That appears to be forcing the attackers to line up their vehicles side by side and bumper to bumper on whatever tarseal is available.

In a war against any peer adversary, the Russian force locked onto that road to Kyiv would long ago have been a smouldering ruin.

The restraint of NATO military planners is explained by their fear that too much military success might invite a nuclear response. That restraint on NATO’s part also demonstrates why it never posed any sort of existential threat to Russia.