"There's no such thing as a tactical nuke" is a common refrain among scholars, albeit skewed toward those not at military war colleges. The argument is that strategic use of a tactical nuclear weapon leads down the exact same escalation path as use of any other nuclear weapon. Moreover, that the very notion of a "tactical nuke" makes escalation more likely. You can disagree, and plenty do, but there's also plenty who don't disagree or at least don't want to find out.
Who are these "scholars" exactly? The only reference I could find is Jim Mattis, and the context was very specific when he said that.
Furthermore, this is a "what if" scenario since tactical nukes have never been used. Of course it would make escalation likely during an open conflict, so what? Doesn't change the fact that there is a material difference between a tactical nuke and a strategic one.
> Moreover, that the very notion of a "tactical nuke" makes escalation more likely.
Sorry, but the notion exists, and the bombs exist. With n=2, likelyhood of nuclear escalation is hard to predict, but access to tactical nukes certainly hasn't increased the incidence of nuclear war so far.
I do think it's pretty hard to actually use a tactical nuke. If you use one against a nuclear power, it seems likely to escalate to mutually assured destruction. If you use one against a non-nuclear power, it seems likely to result in reprisal from the world, including potential nuclear response and therefore escalation to mutually assured destruction. I would think that the yield of the weapon barely matters, it's the fact that it's a nuclear weapon.