Conventional wisdom dictates that Vladimir Putin has ‘miscalculated’ in his invasion of Ukraine. His blitzkrieg has been poorly executed. He has reinvigorated the Nato alliance and the EU and triggered heavy sanctions. And he has lost the ‘information war’ to Volodymyr Zelensky, the TV comedian turned global hero.

But what if the West has ‘miscalculated’ in reading Putin’s intentions? What if the West’s sanctions, along with intensified military aid to Ukraine and a courageous local resistance, encourage Putin to double down? What if he decides to use a weapon of last resort, a nuclear, chemical or biological weapon, even at the risk of World War 3?

At Emmanuel Macron’s latest bout of telephone diplomacy, Putin was intransigent, insisting that all Russian demands are met. Putin also warned that Ukraine’s resistance was putting its statehood at risk, a macabre echo of Adolf Hitler’s Anschluss of Austria in 1938. Macron is said to have concluded: ‘The worst is yet to come.’

It is tempting to assume Putin is bluffing. His actions to date suggest the opposite. Amassing 150,000-plus troops on the borders of Ukraine was not a pressure tactic aimed at securing recognition of Crimea as Russian, a land bridge to the ‘breakaway republics’ of Donetsk and Luhansk, or a formal declaration of Ukraine neutrality to be endorsed by the US and Europe. It was the prelude to invasion.

With the assault on Kiev stalled and bloody urban warfare looming, the US and Europe need to think hard about their objectives. How to increase pressure on Putin’s regime through covert action and arms supplies without resorting to measures such as no-fly zones which could lead to direct conflict with Russia. And how to choose their words carefully. Liz Truss’s incitement to British mercenaries to deploy in Ukraine or US Senator Lindsey Graham’s call for Putin’s assassination were hardly encouraging.

The same cold-eyed calculations should apply to economic sanctions. Over time, they are designed to bankrupt Putin’s war machine. The Swift ban, excising Russian financial institutions from the global payments system, was an important step. So was the decision to target Russia’s central bank and its $600 billion of foreign exchange reserves. A boycott of Russian energy would destroy the price for oil and gas, possibly removing Moscow’s fair-weather allies such as Saudi Arabia and Iran. But would European resolve hold in the face of sky-high energy prices or rationing?

Wishful thinkers believe that economic sanctions may lead to a political implosion reminiscent of the Soviet Union. They should revisit the history books. The Soviet empire collapsed after a long period of decay and the failure of the half-baked reformer Mikhail Gorbachev, a lesson not lost on a generation of Chinese communists or on Putin himself.

In 2019, Putin told me in an interview in the Kremlin that the collapse of the USSR was a tragedy not just for Russia but for millions of Russians left stranded in neighbouring republics such as Ukraine and Kazakhstan. He will do anything to avoid a similar humiliation.

Boris Johnson has declared that Putin must fail. Faced with Russia’s hideous military campaign, it is easy to sympathise with the sentiment – until it comes to defining success and failure. Cornering Putin carries its own dangers. A wiser course would be to encourage a third party, China, to play a mediating role rather than the West sliding into a new Cold War against the two leading autocratic powers.

A truce – not the cynical Russian cease-fire proposals of the past few days – would be an essential first step. The second would be to wean Putin off his maximalist war aims of a Greater Russia. The third, far harder step would be to revisit the idea of neutrality for Ukraine.

Some will say that the moment has passed, such is the savage violence meted out by Russian artillery, Putin’s own nationalist-fascistic rhetoric and Ukraine’s awakening as a nation at war. Against that, a promise of EU (as opposed to Nato) membership, reconstruction backed by China, the US and EU, as well as new conventional arms agreements, might be the basis of a new European security architecture.

The alternative for Russia is a bloody war of occupation, pariah status and a shrinking economy. Putin may have priced in all this and more. If so, we need cool heads, patience and a heavy dose of realism, not wishful thinking about regime change in Moscow. Henry Kissinger, where are you?