Despite categorical statements by US President Barack Obama and a host of European leaders that there will be no military response to Russia's rope-a-dope mix of aggression one day and humanitarian diplomacy the next, European officials were doing a war dance for the cameras on the weekend.

Jose Manuel Barroso, outgoing president of the European Commission, said: "We are in a very serious, I would say, dramatic situation … where we can reach the point of no return."

Arguing that Russia was at war with Ukraine, Lithuanian President Dalia Grybauskaite, declared: "We need to help Ukraine … to defend its territory and its people and to help militarily … because today Ukraine is fighting a war on behalf of all Europe."

That was a cue for Ukrainian President Petro Poroshenko who intoned: "Today, we're talking about the fate of Ukraine; tomorrow, it could be for all Europe."

They were ramping up the rhetoric ahead of a NATO leaders conference in Wales on Thursday. But British and other officials were quick to weigh in, insisting that the only weapon likely to be fired would be another round of sanctions – which surely must have Russian President Vladimir Putin trembling in his boots.

A war for Europe has been a constant in the Kiev rhetoric since early this year, when the Russian president snatched the Crimean peninsula and started running weapons and fighters over his western border.

Crimea on its own is a bit of a bother for Moscow – it is linked to Mother Russia only by air and sea. Hence Putin's one-two punch late last week – a cross-border incursion by Russian forces who, by Saturday, seemingly had disappeared, served to relieve pressure on rebel forces pinned down by the Ukrainian national army in their Donetsk and Luhansk strongholds. But the incursion also unveiled the notion of a Russian-controlled land bridge across the south-east corner of Ukraine, linking Crimea and Russia.

After their unseemly retreat in the face of the Putin push last week, Ukrainian forces were digging in around the industrial port city of Mariupol over the weekend. Oddly, Kiev's security spokesman, Colonel Andriy Lysenko, was declining the help of local volunteers, arguing that the national army was capable of "repelling the Russian military and its mercenaries".

In the same way they repelled the Russians in Crimea earlier this year?

Obama's precise words on Thursday were: "We are not taking military action to solve the Ukrainian problem – I think it's very important to recognise that a military solution to this problem is not going to be forthcoming."

This insistence on ruling out the ultimate sanction chimed with an essay by John Mearsheimer, published in Foreign Affairs, in which the University of Chicago professor of political science argues that it makes no sense to incorporate Ukraine into NATO.

"The reason is simple," he writes. "The US and its European allies do not consider Ukraine to be a core strategic interest, as their unwillingness to use military force to come to its aid has proved.

"It would therefore be the height of folly to create a new NATO member that the other members have no intention of defending."

Provocatively headed "Why the Ukraine Crisis is the West's Fault", the Mearsheimer essay argues that Washington and the European capitals share most responsibility for the Ukrainian crisis because they were the authors of a strategy in which NATO expansion was being used to "move Ukraine out of Russia's orbit and integrate it into the West".

In this they had ignored realpolitik; "and states that ignore it do so at their own peril".

Referring to the vastness of the Ukrainian steppes, Mearsheimer writes: "A huge expanse of flat land that Napoleonic France, Imperial Germany and Nazi Germany all crossed to strike at Russia itself, Ukraine servers as a buffer state of enormous strategic importance to Russia.

"No Russian leader would tolerate a military alliance [NATO] that was Moscow's mortal enemy until recently, moving into Ukraine. Washington may not like Moscow's position, but it should understand the logic behind it.

"This is Geopolitics 101: great powers are always sensitive to potential threats near their home territory."

Mearsheimer makes his point with allusions back to the Cuba Missile crisis of the 1960s and by asking how contemporary Washington might respond if China was to build an impressive NATO-style military alliance, into which it then sought to enlist Canada and Mexico as members.

And that's his point – starting with the Clinton administration in the aftermath of the Cold War, there was a deliberate policy of NATO expansion. He writes: "Logic aside, Russian leaders have told their Western counterparts on many occasions that they consider NATO expansion into Georgia and Ukraine unacceptable, along with any effort to turn those countries against Russia – a message that the 2008 Russian-Georgian war also made crystal clear."

And it's not as though Washington wasn't warned early on.

In 1998, soon after the US Senate had endorsed NATO expansion, George Kennan, the policy-maker and diplomat known as "the father of containment", told an interviewer: "I think the Russians will gradually react quite adversely and it will affect their policies. I think it's a tragic mistake – there was no reason for this whatsoever; no one was threatening anyone else."

After all that, could Thursday's NATO confab in Wales reconsider the organisation's insistence that Ukraine be signed up as NATO's newest member from the old Soviet Union? You know, maybe just push it to a back burner, not to be looked at again anytime soon.