The war-drums are ever so resonant despite Vladimir Putin’s consistent denial that a conflict is imminent. The signal, so to speak, was conveyed on Sunday when the White House national security adviser, Jake Sullivan, warned that Russia could invade Ukraine “any day” in a conflict that would entail what he called “enormous human cost to Ukraine”. This was couched in the caveat that it will happen at a “strategic cost to Russia as well”.

This arguably would imply that there could be no winners or losers. Going by the assessment of the Biden administration, Russia has assembled 70 per cent of the forces it would need to mount a “full invasion” of Ukraine. Mr Sullivan’s presentation is the most ominous picture yet of the options that President Putin has created for himself in recent weeks.

The United States is apparently alarmed by the nitty-gritty of the game theory. During six hours of closed meetings with lawmakers of the House of Representatives and the Senate, senior members of President Biden’s team warned that if Mr Putin chose the most aggressive of his options, he could speedily capture Kiev, Ukraine’s capital, and remove the country’s democratically elected President, Volodymyr Zelensky. Nay more, the invasion could exacerbate the forbidding refugee crisis in Europe as millions might be compelled to flee.

The officials stressed that US intelligence analysts still did not assess whether or not Mr Putin had made a final decision to invade. However, satellite imagery, communication among Russian forces and images of Russian equipment on the move reaffirm that he has assembled whatever he would require to undertake what Mr Biden’s officials said would constitute the largest military operation on land in Europe ever since 1945, indeed the end of the Second World War. They have also warned of human costs if Mr Putin went ahead with a full invasion, primarily the “potential deaths” of 25,000 to 50,000 civilians, 5000 to 25,000 members of the Ukranian military, and at another remove, 3000 to 10,000 members of the Russian military.

The invasion, they contended, could also result in one million to five million refugees, with many of them moving into Poland. By the time the invasion takes place, the Winter Olympics in Beijing will have ended. And this could help Mr Putin avoid antagonizing China’s President Xi Jinping, indeed a critical ally of the Russian President. Russia’s deputy ambassador to the United Nations, Dmitry Polyanskiy, has somewhat predictably denounced the US assessment.

“Madness and scaremongering continues,” he is reported to have written on Twitter. And then with tongue firmly in cheek he has asked, “What if we say that the US could seize London in a week and cause hundreds of civilian deaths? Would it feel right for Americans and Brits? It’s as wrong for Russians and Ukranians.” The verbal duel can only obfuscate the crisis, make confusion worse confounded. Such are the dangers of expansionism.