Despite the war-mongering by Russia’s dictatorship, I think it unlikely we are headed towards a nuclear war for several reasons.
However, as you read this remember that it is a possibility, especially if the U.S. leadership became belligerent – not something Biden is likely to do, nor, for that matter Trump, although the latter because in the past he has acted as if he is a strong Putin supporter anyway as are some other country’s leaders.
So, why would the U.S. and NATO for that matter, NOT respond to a nuclear strike in Ukraine?
The answer, of course, is that they WOULD respond, but not with a retaliatory nuclear strike.
Is it because, as Putin has pointed out, the U.S. was the first, and, so far, the ONLY country to use nuclear weapons in a war?
No, that’s a ridiculous comparison, Truman didn’t order the bombing of two heavily industrialized cities because he was humiliated by facing destruction in a war the U.S. didn’t begin, at least not militarily (sanctions are another story.)
How about fear of Russia’s vast nuclear arsenal, estimated as slightly larger than that of the U.S., somehow neglecting the UK, French, and other NATO nukes?
To that I would only point out that Russia has just demonstrated to the world what many of us already knew, the Russian military is incompetent, sloppy, and undertrained.
Quality v. Quantity
What has that to do with the number of nuclear weapons? Well, as a trained physicist with some knowledge of nuclear weapons, I would point out that an atom and especially a hydrogen bomb sitting in storage will quickly become what might be kindly referred to as a dud.
Nuclear weapons require constant highly technical maintenance, that’s why the head of the Department of Energy is usually headed by a nuclear physicist. Many people aren’t really aware that the DoE is actually the branch of the government which maintains nuclear weapons, they don’t manage gas wells and oil refineries.
So it is likely that many, if not most of Russia’s nuclear weapons are of highly questionable value – they might not work and if there is anything worse than using a nuclear weapon in a war you started it is threatening to use them, and then having one fail to explode. It would completely destroy any credibility Putin has left, even inside Russia.
Finally, there is considerable doubt as to whether the people who actually launch the weapons might be averse to starting down that slippery slope.
It is well to remember that a single Soviet officer stopped a nuclear war by refusing or delaying the launch over what was a simple radar mistake.
(1983, Stanislav Yevgrafovich Petrov)
Here’s why NATO wouldn’t respond with nukes.
First, the U.S. hasn’t been attacked.
Second, no NATO country has been attacked.
We are fighting a surrogate war in Ukraine and the use of a low yield (referred to as tactical) nuclear weapon in Ukraine would actually be rather small.
A U.S. thermobaric (fuel/air) explosive, think of it as a large propane tank mixed with just enough air to explode has the explosive power of 44 TONS of TnT. https://en.wikipedia.org/wiki/Thermobaric_weapon
The bombs the U.S. dropped on Japan to end that war were equal to about 14 thousand tons but a small tactical nuke could be less than 900 TONS of TnT.
That would destroy a large town but Russia has already destroyed many small towns.
Residual radiation from a nuclear explosion could make an area uninhabitable for years.
Would that be the difference?
Possibly elsewhere, but remember that Russian incompetence has already destroyed a large part of Ukraine with nuclear contamination. Remember Chernobyl.
Would the use of nuclear weapons be an existential difference in the conduct of war?
It would certainly frighten other countries and perhaps drive more to join NATO, but practically speaking would it really be such an escalation in this case?
How would the West respond?
India and China, Russia’s only putative allies might or might not join the West in sanctioning Russia but how would NATO respond?
Since China, like the U.S. has a “no first strike” policy, the use of any nuclear weapon by Russia could cause a major break between Russia and it’s current largest oil customer.
China and Russia have always had a strong mutual distrust.
Keeping within Russia’s own rules of engagement, NATO forces might wipe out the entire Russian naval fleet within a few hours using conventional weapons.
Even the Ukraine has wreaked terrible damage to their most advanced naval ships and their naval capability is far less than, say, France’s, let alone NATO or the U.S. which has a fleet larger than all other navies combined.
Cyberwar Or Nuclear War
NATO might also attack Russia in a cyberwar. It is possible that the NSA already has the capability of taking down all Russian infrastructure including its military command and control system.
That might explain why Russia hasn’t attacked NATO’s computer systems – fear of reprisal.
NATO might provide more and better weapons to the Ukraine Army, although those normally require extensive training.
Captured Russian weapons are ones the Ukraine Army already knows how to use. The Stinger anti-aircraft missiles we already supplied are no more difficult to use than a rifle.
For another point of view, see this BBC report.