Everyone saying this ignores the nuclear arsenal. Which Russia constantly reminds everyone of, to the point of no one taking them seriously anymore.

If anyone decides to invade Russia, they better be super sure about their anti-ICBM capabilities. Just one warhead going through the defense means a leveled city. So, 200k-1million+ casualties.

So, who's taking that chance? For what?

> Just one warhead going through the defense means a leveled city.

My understanding is that the majority of Russia's large nuclear arsenal consists of "tactical" warheads, with a yield small enough that they can be used on a battlefield containing Russian forces. These are not city-busters.

Countries like the US and UK, whose nuclear doctrine is "no first use" and deterrence, rely mainly on MIRVed city-busters. The UK submarine force includes some cruise-missile nukes; but it's mainly MIRVed ICBMs. If you launch a single missile, you have launched multiple warheads. I don't know how NATO doctrine is supposed to respond to (say) a single ten-kiloton nuke fired at a railhead or marshalling yard.

I'm not quite sure what your point here is, but if it is that there is no plausible way in which Putin can claim Russia is threatened with invasion from the west, I agree.

Nobody is taking that chance. At the moment. But if Russia shows that they are willing to use their nuclear weapons to the point that it becomes believable that they will do so anyway then we are in completely uncharted territory. Note that this war isn't over yet and that Putin has threatened multiple times now more or less obliquely that he would not hesitate to use nuclear arms in a first strike situation for whatever pretext he seems to think is enough. This was then later walked back again by other Russian functionaries but the damage is already mostly done: Russia is no longer believable, and apparently nuclear first strikes for pretexts are on the table.

I thought they rely on nukes, to deter invasion...

And failing to take the rest of Ukraine might lose them one eventually.

A serious danger is that Putin deciding it's worth a war to take the Bessarabian Gap indicates he might think it's worth a war to take the baltic sea coast.

https://i.imgur.com/0fIjhmB.jpg

Yes, I've been saying that for 20 years. I have a lot of interests and family in the Baltics and NE Poland and this is a main point of worry for me. Russia could make a play for the Suwalki gap in a day or two at most, and then we'd have a real problem.