50 years ago, NATO doctrine was the use of tactical nuclear weapons, but only in response to being overrun. The idea being that a Soviet invasion of Europe was an existential threat. We either do this or all die.

But these guidelines were documented and well-known.

There's a good case to be made for the use of tactical nuclear weapons at some extreme case, the nature of that case might vary. But it is very important to make sure everybody knows what conditions have to be met for this to happen.

We have many more weapons that are much more dangerous than tactical nukes. If we want to isolate them because of the fear of escalation, that's fine. If we want to include them in the mix of options that's fine too. But what we can't do is keep potential adversaries in the dark and then spring them on them. That's because the problem with nuclear weapons is their unlimited ability to quickly escalate destruction. That's the much more severe problem to deal with than what kind of guts make up a particular delivery system.