Apparently wide swaths of the US public approve of the use of nuclear weapons in non-retaliatory circumstances.
Randomly selected groups of survey respondents were told that the nuclear and conventional attacks would either be equally effective or that the nuclear attack had a greater chance of success. Everything else was held constant. When both options are equally effective, only a relatively small proportion of respondents prefers nuclear weapons, presumably to “send a message.” Yet, when nuclear weapons are portrayed as having a 90% success rate while conventional weapons hit the target with only 70% of the time, a (small) majority of Americans prefers nuclear weapons to conventional ones. This effect is even greater when the discrepancy in success rates widens further. Moreover, among the people that still prefer conventional weapons, most say that they do so not out of moral aversion but because they are concerned that first usage sets a dangerous precedent.
There’s obviously an elite-popular divide, because virtually no one in either party in DC has talked seriously about the use of nuclear weapons in a preventive war against Iran. Such was not the case fifty years ago, when preventive nuclear war was seen as a good options by some policymakers, but that simply illustrates how taboos develop over time. I’ve also never seen any evidence that anyone ever seriously discussed using tactical nuclear weapons in 1991, even against Iraqi military forces or suspected missile sites/chemical warfare facilities. Bush was fairly cagey about whether the United States would respond to an Iraqi chemical attack with nukes, but nobody ever seems to have proposed “let’s blow up this Iraqi tank column with a 30kt bomb.” Recall that the US military expected significant casualties (~10000) in the course of destroying the Iraqi Army, so nukes could genuinely have been expected to reduce direct military costs. The elite level taboo, presumably, is why no one thought in these terms. The reason for the divide is unclear; we don’t normally think of the US foreign policy elite as being more pacifistic than the population as a whole, but perhaps the answer lies in exposure to transnational norms.
I’d certainly like to see comparative data from the other nuclear states. My way out guess would be that you’d find similar or higher levels of support for non-retaliatory use of nukes in Russia (Russia still publicly talks about using nuclear weapons while at a disadvantage at conventional levels of escalation), relatively high support in Pakistan, China, India, and maybe Israel, and very low support in Britain and France. But that’s just guesswork.