I’ve heard that the Russians, being convinced that the best defense is a good offense, didn’t believe in flexible response: as soon as the first tactical nuke exploded over a Soviet tank column, they’d immediately launch a full-scale strategic continental attack against the USA.
On the other hand they are also big believers in putting up an aggressive front, so what they would actually do is questionable. They’d say something like that regardless of their actual intentions; it doesn’t mean they’d actually commit suicide like that.
This^^.
They were also far more disciplined and on-message as an organization than was the USA what with the separate civilian administration, former advisors and officials, DoD, DoS, various congressmen & former congressmen, think tanks, and individual academics each purporting to speak for (at least part of) the whole with their pet POV.
The only thing harder than divining how much the one Soviet official position was sincere vs. a lie was divining which of the 25 quasi-official positions of the USA was the one actually in force. 
I recall reading a comment by an ex-Soviet official after the Cold War how the election of Reagan made the Politburo seriously consider a nuclear first strike on the US, because they thought he might decide to nuke the world for Jesus. Thanks to how much Reagan appeared to buy into the End Timer Rapture idea that a nuclear war was desirable, calling the USSR and China Gog and Magog and so on.
Lest we think that it was only the USSR that was scary.
I’d almost argue that the US takes some measure of pride in having been the only country to use nuclear weapons in combat, and the rest of the world knows it.
I don’t think the US, government or people give half a shit what the rest of the world thinks about that, honestly. First, it was 80-some odd years ago, and second, it ended the war with less loss of life than a conventional end would have required.
That is the question, isn’t it? It seems like there are loose cannons on our side, and a whole lot of unpredictability and limit-pushing on the other. Neither of which are good in their own right, but the combination is scary, to put it mildly.
In the 90s or the early 2000s, north Korea didn’t have a nuclear weapon yet. Nuking north Koreas nuclear facilities and military facilities may have helped bring down the regime.
However NK still had chemical weapons, biological weapons, artillery pointed at Seoul, and special forces designed to perform invasions. So things would still be pretty miserable in that war. But North Korean has been a major nuclear proliferator helping Iran, Syria, Pakistan, Myanmar, Libya, etc advance their nuclear programs. North Korea is helping endless dictatorships develop nuclear weapons.
It’s an ends vs. means argument, but I think it comes down to the results. We know how it ended with the nukes. There’s no way of proving it, but my guess is that without those two nukes, Japan would probably look more like the Philippines or Indonesia do today, even in a best case non-nuke scenario.
When has something like that ever worked (in the sense of not escalating a conflict)? I mean where an enemy launched an attack so massive that the other side said “yeah, this aint worth it”? And particularly when the other side is the United States, in possession of the greatest military and economic might in the history of mankind with a propensity to decide these sort of things are “worth it” long after they actually are?
It’s my understanding that back in the day before guns, this was fairly typical. I think a lot the conquests made by the Mongols during the days of Genghis Khan, for example, followed that pattern. I think a fair chunk of the Roman Empire back in the days of Julius, Augustus, Tiberius, etc. was also conquered in a similar way, especially in the west. It wasn’t always major battles against a near peer like the Parthians or battles to the bitter end like with the Jews at Masada. There was some amount of people just surrendering and agreeing to become part of the empire. Then there were the various conquests during the days of European imperialism, like Cortez against the Aztecs, Pizarro against the Incas, and so on.
I’d suggest that Russia’s nuclear threats did succeed in deterring the West from intervening, no actual detonations needed. There haven’t been and will never be any NATO boots on the ground. A few billion dollars here, a few assorted pieces of surplus equipment there. Enough to help Ukraine survive but not win. We’ve failed them.
Much has been made of how Biden supposedly faced down Russia’s nuclear “red line” threats by allowing strikes inside Russia, or sending a few dozen Brads and Abrams, but this really just shows how successful Russia has been in lowering the bar for what counts as boldness.
To be certain, Russia is paying a ghastly cost for a Pyrrhic victory that won’t include regime change in Kyiv. But they’ll lock in most of the territorial gains they set out to achieve. Russia will win, Ukraine will lose. The nuclear bluster worked.
Back in the Cold War the question was whether the USA and it’s allies would risk a nuclear war over West Berlin. Kennedy felt it was important enough to draw a line in the sand and declare “Ich bin ein Berliner”
IIRC, the prevailing winds in that section of the world blow southwest to northeast.
It’s unwise to detonate a nuke somewhere if you’re the next country downwind. (Fallout effects could be reduced by using an airburst, for example, but you’d still be dumping radiation into the evironment by irradiating the bomb components and letting them drift on the wind.)
To be sure, in the nuclear era, there aren’t many case studies we can go by. But the key element is that Ukraine wasn’t America or even a direct-treaty American ally. It wasn’t like Russia was striking Chicago or Warsaw.
The Biden administration was still reeling from the Afghanistan-withdrawal debacle half a year earlier in Aug-2021, and now imagine a few Russian nukes detonated in someplace relatively harmless like flat land or the Black Sea. Who would stand up and say, “We need to send a lot of weapons to the Ukrainians, even though Moscow just scared us shitless with those mushroom clouds?” Even right now, when Russia hasn’t used nukes, the West is already acting all timid, as HMS Irruncible pointed out. As has been widely criticized, Biden and Sullivan viewed the Ukraine invasion as “a crisis to be managed, not a war to be won.”
So if the West has been so chickenshit timid even when Russia has not detonated any nukes, how much more intimidated would the West be if Russia did set off a few nukes?
The United States was willing to intervene to reverse Saddam’s invasion of Kuwait in 1990 because Iraq was all-conventional and the implications of oil in the Persian Gulf were big. If Saddam had nukes and had detonated a few as a warning, it probably would have been a whole different story.
Possessing nukes allows a country to say “f*** you” to the United States. That’s the key thing driving proliferation.
That hasn’t always been the case. Back before it turned into a grinding attritional slugging match that failed to achieve meaningful results, there was a lot of belief that the 2023 summer counteroffensive by Ukraine was going to cut the land bridge to Crimea and even liberate Crimea. The constant Russian offensive failures and the success of the Ukrainians in driving Russia back from Kiev and the sudden and swift counteroffensive at Kharkov seemed at the time to make such an outcome plausible, even likely.
What would have been the outcome of that politically? China and India have already made their feelings about the use of nuclear weapons abundantly clear. They’d have cut ties with Russia along with the rest of the world. The political and economic fallout for Russia for the invasion of Ukraine would have been absolutely devastating. And to what gain militarily? What would detonating a few nukes in somewhere “relatively harmless” like flat land or the Black Sea accomplish?