Obviously, "unthinkable" is now struck out. Two weeks ago it was (at least for civilians around here) unthinkable that Putin would invade Ukraine (and many Ukrainians seem to have been of a similar opinion). Last week it was unthinkable that Russia would start to level Ukrainian cities. What's unthinkable this week?
Yup I was that idiot. Still I think it is even more stupid to start WW3 right now rather than act in response should that abomination of human decide to attack Europe. If we do not attack there is still a chance and a good one for that I think. If we do the chance might still exist but I think it would be pretty slim and do we really want to test it.
Sweden/Finland have a complicated status with NATO. It's long been understood that extending NATO up to Russia's borders would trigger a response, which is why those countries have always partnered with NATO but never been technically a member. Indeed, through this whole debacle, the folks with brass balls have been the Swedes and the Finns.
Ironically, that is part of Putin's public justification – that Ukraine may gain Finnish status. But the reality is that Sweden and Finland are very much socioeconomically Western, whereas Ukraine is not, which is partly what makes Ukraine much harder to defend. In order to defend them, they need to be part of the polity. The EU has already had a hard enough time with Poland and Romania.
There's already a bunch of NATO countries bordering Russia in Europe. Maybe not to such a large extent that Finland would be, but there definitely is.