I agree there are some similarities here and 2) applies—though is a bit more gray as I don’t think Israel has openly acknowledged it has nukes (but must admit I have not followed or gone looking). But I don’t think that leads to WWIII as it would still be a proxy war that most would think remained regional.
I think the most obvious reason is that Putin has said:
He/Russia is threatened by NATO
He thinks a nuclear first strike is acceptable if Russia is threatened.
The claims that Russia is itself threatened (or is claimed to be to justify actions) is the main difference here I think.
Isn’t this similar to the issues between Israel and Iran? Or does 2 not apply there?
I agree there are some similarities here and 2) applies—though is a bit more gray as I don’t think Israel has openly acknowledged it has nukes (but must admit I have not followed or gone looking). But I don’t think that leads to WWIII as it would still be a proxy war that most would think remained regional.
Israël definitely has nukes, they just refuse to acknowledge it.