There’s no technically feasible way to use nukes such that the benefits exceed the costs. So, he won’t.

It was one thing for the U.S. to drop two atomic bombs on Japan, when the latter was clearly militarily defeated, and at a moment in history when nuclear weapons had never been used before in war and no one else had them.

Regardless of the wisdom or lack thereof, the results of the Hiroshima and Nagasaki bombings were clearly horrifying. Hence why nuclear weapons have never been used offensively by any nation ever since. That includes wars fought by both the U.S. and USSR that resulted in “losses” (Vietnam, Afghanistan). And including, notably, the Korean War just a few years after WWII that was fought to a bitter draw — when Truman, the same President who ordered the Hiroshima/Nagasaki bombings, was still in power.

Hiroshima/Nagasaki therefore did not create a “precedent” in favor of dropping nukes, as Putin claimed in a rambling speech, but rather serves as an “exception that proves the rule.”

The nuclear taboo has held for decades. Putin’s military debacle in Ukraine doesn’t justify breaking it whatsoever. Further, there is no feasible way for Russia to use nukes in Ukraine in a tactically beneficial way, without exposing his own troops and civilians to radioactive fallout. Doing so would also invite a massive NATO conventional, and possibly nuclear, intervention on Ukraine’s behalf. Putin’s regime, already teetering, would crumble.

So, he won’t.

If I’m wrong, and Putin does so anyway, then the fault and the consequences will be entirely on him.

Oh no, there will plenty of consequences to go around.

Sure. A nuclear war would bring a lot of pain, loss of human life (now and for decades to come, as radiation takes its toll) and disruption of the global economy. That said, Putin launching a tactical nuke at a mudfield in Eastern Ukraine doesn't necessarily mean that Milwaukee is getting hit with nukes tomorrow.

But it does mean cancer for a lot of Europeans.

True. Dying of radiation-caused cancer in 20-30 years is bad. Dying of a Russian boot to the face next week is even worse. War doesn't afford great choices.

I think that's why Ukrainians (who have direct experience of the evils of both Chernobyl, and of USSR/Russian imperialism) are fighting Russia in spite of all these nuclear threats, and why most of formerly-Soviet Eastern Europe hasn't wavered in its equally forceful support of Ukraine.

Technically, a nuclear strike on China during the Korean War might have had its benefits - the USA was still being ahead in nuclear arms, and the consequences were manageable since the Russians may have had protested loudly but secretly might have sent a crate of caviar to Truman with a "Thank you for bombing our enemy"-card while China would have been on its knees.
No Kim clan firing rockets over Japan and all of Korea being united. Well, we'll never know.

But when I look at the NATO of today...frankly said I'm worried. For one example, what does Putin have to lose when using tactical nukes? Putin knows that there will be lots of debates and hesitation on the Western side about an military engagement plus he still has the advantage of being the "home team". A home team still supported by a majority of Russians of which many are crying for the extermination of the Ukrainian people, I have to add.
It might have looked different if the NATO had engaged in the first days after Putins invasion of the Ukraine by driving out all Russian forces, but this opportunity has been given away lighthearted.

As much as I like to see Putins ass getting kicked around the block, I'm afraid that the war will drag on for years unless there's a Russian Elser or Stauffenberg who are disposing him with the goal of establishing peace and democracy (currently, it's more likely that a disgruntled oligarch orders a hit on Putin because of the personal wealth melting away).

The details of MacArthur’s plan to use nukes in Korea were, apparently, to detonate as many as 50 of them along the North Korean border to deter the Chinese from sending over more troops.

Though I’m no military expert, this seems like a totally batshit war plan. Whatever short-term merit it may have had (even assuming it would have resulted in total victory on the Korean Peninsula) would have been far outweighed both by devastating environmental consequences, and by opening the floodgates to massive nuclear proliferation around the world and inevitably more use of nukes by other nations in the 20th century.

The fact that Harry Truman, the only world leader in history to ever order a nuclear strike, declined to do so in Korea even while facing potential defeat was, in retrospect, a far-sighted decision that was key in establishing the nuclear taboo that prevails today, and that we all benefit from.

Now I obviously don’t know what kinds of nuclear war-games Putin & Co. are cooking up now (if any), but it seems clear to me that the markedly abysmal progress of Russia’s conventional forces (after months of combat, establishing control just a few miles beyond Russia’s border) means that any even remotely conceivably militarily justifiable nuclear strike in Ukraine would have to take place far too close to Russia’s own borders to be worth it. Even if the West did nothing in response to the provocation, what would it gain?

It’s one thing to order a nuclear strike on a faraway land, as the U.S. did in Japan — quite another to detonate nukes in the fallout range of your own people. Even in famously repressive Russia, it’s hard to imagine the Russian state continuing to carry the confidence of its own people after that.

If, on the other hand, Putin really is planning on nuking Kiev, London, Paris, New York, Los Angeles, and the other main population centers of Western humanity, there’s little we could really do about it except bomb Russia to oblivion in response (the old Cold War concept of MAD).

It’s quite possible that we see a stalemate settle in between Ukraine and Russia in the eastern provinces, just the same as it had existed in the Donbas region since 2014. Not a good outcome, but if there’s no diplomatic solution in sight, then it’s maybe the least bad one available.

As far as I know, Mac Arthur had also optioned for a nuclear strike on Chinese cities like Shanghai, and I guess that this was the final straw which made Truman fire him.

I'm no military expert either, but for one fact it was always a part of the Soviet and apparently Russias military doctrine that human life is cheap when to achieve a goal and as historic and current events show still being valid. Besides - and I can't stress it often enough - a majority of Russian people are behind Putin and his "Special Operation" and an quite scary high number of influential Russians are calling for the use of tactical nukes in the Ukraine.
As long as these nukes are detonating not too close to the border of Poland...well, Putin is the Outlaw #1 anyway, and when push comes to shove I think he will use them.

Deescalation is not a part of Putins strategy, as his tactic of continuously stepping up the conflict shows. And so far, it had worked for him, as the US, EU and NATO are still limiting themselves on reacting and tinkering around each time Putin is holding up his stick.