The Russian president has stampeded both Finland and Sweden, two neutral countries of long-standing (almost eighty years for Finland, over two hundred for Sweden), into joining the NATO alliance, the very ‘threat’ that Putin claimed he was trying to drive away from Russia’s borders. Finland has a 1,300-km. border with northern Russia.

The Swedish and Finnish response to his invasion of Ukraine would have surprised Putin. He would see no connection between his invasion of Ukraine, a former Russian imperial possession that needed to be whipped back into line, and two independent countries that have not been in Russia’s sphere of influence for over a century.

They, on the other hand, did see a connection. A neighbour they previously rated as dangerous but rational had suddenly revealed himself to be an aggressive and probably irrational gambler. No fully sane and competent Russian ruler would have attacked Ukraine with the inadequate forces and haphazard, overconfident strategy that Putin employed.

You might think that Putin’s sheer incompetence would be reassuring to the Swedes and the Finns, but it was not. On the contrary, it frightens them, because they are very much in the same position as Ukraine militarily: relatively small countries (Sweden has ten million people, Finland five million) with very good military forces.

I can vouch for this personally because in the course of making a documentary film about neutrality I spent time at sea in the Baltic with Swedish fast attack boats out of Karlskrona, and with Finnish reservists on exercises between Lappeenranta and the Russian border.

With a little practice and close-up access, you can tell which militaries are the real deal and which are just chocolate soldiers. These were people who knew what they were doing and did it with quiet efficiency. They would give a very good account of themselves if their countries were ever invaded.

They might even be able to stop the Russians dead (and nobody else is in a position to invade them). That’s why the Swedes chose neutrality: they reckoned they were safer that way. If there were a general war, they were not a strategically vital place and they would be very costly to invade, so maybe the major combatants would just leave them alone.

The Finns had neutrality thrust upon them by the Soviet Union after the Second World War. They lost a lot of territory to the Russians, but they fought hard enough that Moscow let them be neutral rather than reducing them to satellite status.

So why have both countries now decided to join NATO? They are still such tough nuts to crack that they could probably stop the Russians by themselves if Moscow was also engaged in a war with NATO. And why would the Russians attack only them alone? Stay neutral, and even in the worst case the Russians will probably pass you by.

That remained a valid assessment until 24 February 2022, and then it suddenly wasn’t. Putin invaded Ukraine, probably to the astonishment even of his own entourage, and from the start began issuing veiled warnings about resorting to nuclear weapons if he was thwarted.

The Russian attack in Ukraine bogged down almost at once, as it was bound to do unless the Ukrainian army was utterly useless. Too few Russian troops, too many lines of attack. And the hints from Moscow about resorting to nuclear weapons to compensate for a conventional defeat multiplied.

This is crazy stuff, and all military skills and hardware the Baltic countries could bring to bear in a conventional war would be irrelevant if they were faced with similar Russian nuclear threats themselves.

The only effective counter to a nuclear threat is a credible promise of nuclear retaliation. Sweden and Finland have no nuclear weapons, and the only way they can have their security guaranteed by a nuclear deterrent is to join NATO. So that is what they are doing.

The Swedes still don’t like nuclear weapons, and Prime Minister Magdalena Andersson emphasised that Sweden will not allow foreign troops or nuclear weapons to be based in the country, but the deal is done.

Turkish President Recep Tayyip Erdoğan is demanding that the two Baltic countries expel some anti-Turkish Kurdish activists as a reward for not vetoing this NATO expansion, but this problem will be finessed. It will take months to do the legal work, but in practice, the two Baltic countries are already covered by NATO’s nuclear guarantee.