In Moscow, the question has become well-worn since the little war in Georgia in August 2008.

The fans of Vladimir Putin ask it with equal conviction of Ukraine. How would the United States feel if Canada and Mexico signed up to a hostile military alliance?

There's paranoia, presumption, bluster and an old Russian world-view wrapped up in a single inquiry. Within it there is also more than a grain of truth. As the House of Lords committee on foreign affairs has just argued, a failure to understand the mixture has led to a "catastrophic misreading" of the Ukraine crisis by Britain and its allies.

That's dangerous, of course. It is not addressed by Philip Hammond, the Foreign Secretary, denouncing Mr Putin as the equivalent of a "mid-20th century tyrant", or by Lord Robertson rattling his Trident. The Russian president is in a long line of autocrats in a country with limited experience of democracy. Britain has been dealing with those since before our own Crimean War. Yet their lordships charge that the Foreign Office has lost the diplomatic knack.

Of itself, that's faintly shocking. Proponents says we must have Trident as insurance against possible threats. Lord Robertson, for one, specifies events in Ukraine as a "manifest" risk to Britain's security. Yet it transpires that our chaps lack the language skills, according to a former ambassador to Russia, to conduct diplomacy adequately with those we might want to deter. Are we even sure of what is being said?

I exaggerate, but only a little. Britain and Europe have been "sleepwalking" into the Ukraine crisis, according to the committee, because of ignorance and because of a failure to grasp the depth of Russian hostility towards European Union and Nato expansion. This is both true and bizarre. After all, Russia has been making ominous noises about both programmes for years. Like the incursion into Crimea, Moscow's recent interference in Ukraine didn't come out of the blue.

If language skills are sketchy, an ignorance of history seems absolute. If western governments did not anticipate likely reactions to the steady eastwards push of the EU and Nato they either ignored precedent, deluded themselves that geopolitics had altered permanently with the fall of the USSR, or simply didn't know enough.

There are three basic themes in even the simplest histories of Russia. One is the appeal to Slavism redefined as Russian nationalism. The argument has been going on since Peter the Great built St Petersburg as his "window" to the west. Throughout the 19th century and since the retort has come that Russia is of the east, not Europe, and should never attempt to pretend otherwise.

Sometimes Mr Putin has seemed to embrace this sort of nationalism, sometimes he has simply manipulated it. He will, on occasion, dismiss western notions of democracy as irrelevant to Russia. Equally he will say, of Russians and Ukrainians, that "we are one people". Just a year ago, addressing both houses of the Federal Assembly, he said, "Crimea is primordial Russian land" and "Kiev [capital of Ukraine] is the mother of Russian cities".

Needless to say, this isn't quite how the west likes to see things, but it helps to explain Mr Putin's popularity in Russia, despite sanctions and an economic crisis. The idea that Ukraine is not essentially Russian is a minority opinion. A Cossack vassal state was abolished by Catherine the Great as long ago as 1764. In 1922, Ukraine was deemed a founder of the USSR. For those who applaud Mr Putin, the idea that the birthplace of the Kievan Rus could somehow declare independence in 1991 is the aberrant notion.

But there's the second textbook theme. For all the Soviet lip-service paid to national self-determination, and for all Mr Putin's pretence that he presides over a harmonious greater Russian family of nations, the experience of democracy has been limited. Arguably Russia has never been governed in the western style. Its president, elected or not, is as autocratic as any tsar. The free choices of formerly subject peoples do not interest him much.

Like the Romanovs, like the Stalinists, Mr Putin conducts his foreign policies according to another old Russian obsession. Odd as it might sound, the biggest country in the world fears "encirclement". It considers itself to have enemies and former enemies on every side. It creates buffer states - and has always done so - at every opportunity. From the Kremlin's point of view there is nothing benign about the growth of Nato or the expansion of the EU. These are, as the apparatchiks of the USSR would have said, "provocations".

That's is not, or not entirely, a fantasy. A full dozen states once within the Soviet sphere have joined Nato after serving apprenticeships with the treaty organisation's American-organised "Partnership for Peace". Seven former eastern bloc countries joined the EU in 2004, with another two - Bulgaria and Romania - joining in 2007. The union and Georgia have an "association agreement". Ukraine has signed the same treaty and was a "priority partner" of the EU even before the overthrow of the Viktor Yanukovych regime.

That leader - elected without controversy, as the west always forgets - began to lose power when he chose to submit to Mr Putin's pressure rather than bind Ukraine closer to Europe and Nato. One fact was seized on, the other overlooked, despite the unambiguous lesson taught by the Kremlin to Georgia: independent or not, the Ukrainians would not be allowed to complete Russia's encirclement. That, more or less, and despite sham peace talks, gets us to where we are today.

For Mr Putin, it all makes perfect strategic sense. Why seize Crimea first and foremost? Because it was simple enough to seize and because - a basic imperialist calculation - Sevastopol was and is home to the Russian Black Sea fleet. Russia would no more stand for the loss of that base than stand, as the US once planned, for anti-ballistic missiles being sited in Poland.

None of this is pretty. None of it has much to do with freedom or the rights of nations. The west's desire to guarantee those rights might (you never know) be as selfless as its desire to confront and contain Mr Putin. Where Britain is concerned the Lords committee makes a sobering and serious charge: the government doesn't know what it's doing, or why. It has not done enough, yet when it has acted it has failed to anticipate the consequences.

All this, remember, while supposedly shouldering the responsibilities falling upon a signatory to the 1994 Budapest memorandum committing this country, and others in Europe, to protect Ukraine. Lord Robertson's nukes are, needless to say, irrelevant to the problem. Purging the City of London of Russian oligarchs - though their lordships don't go that far - would be a far more effective contribution.

Mr Putin offers a test that Britain fails to meet. The fact sheds a light on Westminster's nuclear pretensions. But as a joke doing the rounds a couple of weeks back pointed out, while Germany's Angela Merkel and Francois Hollande of France were flying out for talks with the Russian leader, David Cameron was busy. He was visiting the set of Emmerdale.