Where does it end? Vladimir Putin has now made plain the way he sees the world. Ukraine, he declared on Monday night, is made up of “what was historically Russia” and its claim to statehood has never been legitimate. Thus, the claim to nationhood of a country that voted by more than 90 per cent to become independent after the fall of the USSR is airbrushed out of history.

Here’s the stomach-churning fact for everyone else east of Berlin: there is an awful lot of land in Europe that a Russian imperialist might define as being “historically Russia”. How much of it will Mr Putin generously decide to reunite with the motherland?

The answer surely depends on Nato: Mr Putin’s territorial demands ultimately only end at the point where Nato countries are willing to make them end. That is the logic of his angry address to Russia and the world on Monday.

The problem with the old Soviet Union, he argued, is that it wasn’t ambitious enough. All of the territories it controlled as Soviet republics should always have just been Russian provinces, he declared, if only the Communist Party hadn’t given too much away to nationalist demands. Mr Putin isn’t nostalgic for the heyday of the USSR. He’s reaching for the tsars.

To take this entirely seriously for a moment, it implies a truly breath-taking territorial shopping list. At a minimum, all three Baltic states, Finland and much of Poland, Moldova and Georgia can wave goodbye to sovereignty. Some parts of Hungary, Romania, Bulgaria and Slovakia are surely on the table. Eastwards, Kazakhstan, Uzbekistan, Turkmenistan and Kyrgyzstan might all need to reassess their national maps. Hell, why not even throw in Alaska? It was once “historically Russia” too.

Here is what history will record as the UK’s iron-fisted response to this doctrine of megalomania: we froze the assets of five banks and three Russian oligarchs. This, apparently, was the devastating package that Boris Johnson had promised to unleash the moment “the first Russian toe-cap” crossed the border into Ukraine. Perhaps he was wriggling out on a technicality: tanks, as far as I’m aware, don’t have toecaps.

He called it “the first barrage of what we are prepared to do”. But the military metaphor only serves to draw more attention to the pathetic reality that the West is turning up to a gunfight with a spreadsheet – and it’s not even a very powerful spreadsheet at that.

Russia has spent the years since the 2014 Crimea sanctions making itself almost financially impregnable. It has a ready supply of dollars from its oil and gas sales and hardly needs to borrow externally at all. So the only way even to ruffle Mr Putin’s feathers is to go after the wealth and prestige of his cronies with the same degree of commitment and force with which he likes to invade countries. Three oligarchs, I suppose, is a start.

Berlin has at least surpassed its much-debated aid package to Ukraine of 5,000 helmets by declaring that Nord Stream 2, Mr Putin’s coveted new gas pipeline, isn’t going to be certified. This is substantial progress, given the lethargic state of German public opinion on Russia up to now.

But even this act of resolution looks uncertain. The certification process has been suspended; Berlin has not quite said that it will be legally unwinding the pipeline, and the construction is already complete. Are we going to see Germany dismantle the thing?

Our ultimate problem is that we have spent too many years saying things we don’t mean, and Moscow is calling our bluff. After all, Ukraine was never a Nato member, but it still supposedly enjoyed a Western guarantee of its territorial integrity.

It would be wise for Western leaders to stop exaggerating their resolve and over-promising all sorts of tough actions that never materialise. It’s the sort of mistake that, uncorrected, winds up landing us all in a confrontation between nuclear-armed powers.

Let’s instead focus on two things: delivering the “severe” sanctions our governments have talked so much about and then working out what Nato’s new red line really is and how the alliance will declare what it is and credibly defend it.

Mr Putin has staked a new claim to imperial domination. Nato must answer him with more than a fresh onslaught of empty words.