It's really hard to guess how retaliation would happen in practice, a large-scale nuclear war certainly isn't inevitable.
The most likely targets for nuclear strikes right now are also non-nuclear states.
It's scary, but in some scenarios one nation can absolutely nuke another nation without threat of getting nuked themselves. In reality, the cat coming out of the bag looks more like that than nuclear armageddon.
Game theory works when players know the payout matrix. When the assumed payout matrix is shown to be false, you get very chaotic, almost random results, because you can't assume that your opponents will correctly choose the rational choice. With WMDs, the consequences of that can be deadly. That's why both nuclear proliferation and "limited" nuclear war are such fraught choices, and why the major nuclear powers have worked so hard to avoid them. They've run the game theoretic simulations and understand that it doesn't lead anywhere good.
I agree with you. It's really bad and it's a slippery slope. It's also true that there are many scenarios where you can launch nukes without repercussions. That's the misperception I'm pointing out.
It's scary, but it's fine!
In 1998 neither India nor Pakistan were considered members of the nuclear warhead club.
Then India detonated 5 warhead sized kiloton and sub kiloton class thermonuclear (fusion / hydrogen) weapons .. and within 20 days Pakistan responded with six atomic tests (non fusion, larger than warhead size).
The interesting thing about that exchange is that India suprised the world intelligence community pants down with capability and execution, and Pakistan's speed of response was equally suprising.
Despite the spectacle of rapid cross fire of eleven nuclear weapons and tense international responses the small nuke treats didn't escalate into anything larger .. and likely served to keep heads a little cooler wrt both India and Pakistan.
All up there has been > 2,000 nuclear detonations across the globe, some definitely intended to intimidate or otherwise push the envelope of possibility.
In that light another small nuke that avoided civilians and had a military target is unlikely to escalate although it would certainly cause a collective intake of breath and give pause.
I said Russia dropping a nuke on a Ukranian military site will not escalate into a nuclear war. I say this because so many people assume that it would and it makes no sense.
Of course, other options such as biological weapons have been explored in the past. Ukraine wouldn't necessarily have to invest all that much to prepare retaliatory operations capable of killing millions of Russians in the case of a nuclear attack.
The only problem with such less orthodox means is that they're almost necessarily covert, and therefore can provide limited deterrence. "We have ways to impose immense costs if necessary" just doesn't sound that scary when the means are a secret.
