I practised law in Central and Eastern Europe. My old firm had offices in both Moscow and Kyiv. I lived in Warsaw (11 years) and Moscow (7 years). The region is where most of my friends are, including both Russians and Ukrainians.

I am pleased to see some of the former putting dove of peace emblems on their social media profiles. It says much about Russia that I worry it may have adverse consequences for them. One of my Ukrainian friends was interviewed on BBC radio recently. It was chilling to hear his usual calm, reasonable tone as he talked of joining a citizens militia and preparing to resist invasion. He and I were law partners. I fear for his safety and that of his family. He was born to a Ukrainian family in Canada and had the option to leave. I respect and admire his decision to stay and fight. I hope, in his position, I would have his courage. As his friend, I wish he was in Canada.

I hoped against hope that Putin was sabre-rattling. Part of the secret of his success has always been that, one way or another, he keeps Russia in the western news, which soothes his electorate. Why? Because it was a shock to their collective psyche to descend from being one of two super-powers to just a regular nation with an economy the size of Belgium's. Britain struggled psychologically in descending from being the greatest empire in history to just another G7 nation, but we had decades to adjust. We had time to build such institutions as the Commonwealth to soothe the jangled psyches of citizens used to red world maps in their classrooms. Russia had only days.

I am not excusing Putin's aggression by saying the West has made terrible mistakes in handling the demise of the USSR. They flowed not from malice but from a naive, innocent and as it turns out optimistic belief that Russia would rapidly become just like us. Fukuyama's book The End of History and the Last Man (published as I moved to Warsaw) pretty much summed up our leaders' attitude in that respect. The West simply did not feel the need to take the Russian elite's paranoid views on NATO seriously. It saw Russia just as a new, economically-insignificant, member of the Free World. 

NATO was an anti-Soviet defensive alliance. Its weaponry was trained on Russia and the Warsaw Pact. When the USSR ended, it should probably have been disbanded precisely because Russia's military and intelligence communities (who, unlike in other Warsaw Pact countries, were not purged after the fall of the USSR) had grown up thinking of it as "the enemy." They felt threatened by it. That feeling was unjustified. NATO was a defensive alliance with a "no first strike" doctrine. It poses no threat to Russia now and, in fact, never did. The feeling is real though. More accomplished diplomats than ours would have understood its significance.

If post-Soviet Russia's economy had been bigger, it might have been listened to. Ignoring the fears of its generals and spies because it was now a country that didn't matter very much seems in retrospect to have been an error. It won't help a paranoiac to laugh and say he doesn't matter enough for anyone to be out to get him.

This became a worse (but still unrecognised) problem when Putin and his chekisti (ex-KGB men) came to power. The military, intelligence and political communities were in practice just different arms of the Communist Party in Soviet times. Real democratic politics was in its infancy when Putin came to power. Once he was in the Kremlin, Russia's political elite was once more completely aligned with the attitudes of old KGB guys like him.

I suppose we in the West thought we could just rewrite NATO doctrine and retarget its weaponry to handle other threats. NATO worked, so why not repurpose it? The other Warsaw Pact countries, after all, cheerfully applied to join. I was in Poland when that happened and can assure you my friends there still saw it (having had the same education as their Russian contemporaries) as an anti-Russian alliance. That's exactly why (knowing Mother Russia rather better than we did) they wanted to join! I mentioned to a person I met from the Foreign Office at the time that I thought it was a mistake because Polish attitudes were (a) entirely contrary to NATO doctrine and (b) likely to fuel Russian paranoia. She said (I quote from memory, but I am confident it's pretty accurate);

The Foreign Secretary privately agrees with you but the Cabinet doesn't. Anyway the Americans wouldn't hear of excluding Poland.

So while we in the West sincerely saw NATO expansion as harmless (and would probably have accepted Russia as a member, with some conditions) the Russians didn't. Neither did some of their former allies who were joining it – and the Russians knew that. We are not responsible for their paranoia, but we did feed it. 

That said, Putin is lying comprehensively in his depiction of NATO. There's a useful (and very mild) web page of refutations from NATO itself, which is well worth a read. He is just spinning a yarn to justify doing what he wants to do. He's pretty clearly expressed his view that the Ukraine has no right to exist as an independent nation. My hopes have failed. He's about to fix that "error" and, in so doing, write himself into Russian history as (he thinks) a hero. 

The Putin of my days in Moscow was cleverer than this. He knew that rattling his sabre was enough. I fear that his isolated life for so long among people too scared of him to tell him he's wrong has caused him to lose his mind. I don't fear for the West, which could defeat his armies as readily as we could defeat those of Belgium, I do fear for my friends in the region.

I explained to a Ukrainian lady I met yesterday that – while I could understand if she had no time for that at the moment – I feel sorry for the Russian people. They are a wonderful, cultured people who have almost always been badly led because of endemic corruption. The end of the USSR didn't end that, as anyone who'd read Gogol could have predicted. Russia didn't stop being a problem to the West when the USSR fell. It may prove to become a worse problem now because the old Communist leaders always responded rationally to circumstances. I fear this madman won't. 

The West's leaders must perform better now than they have so far because how they respond could expose the world to much more than the loss of Ukraine's independence.