Earlier quoted context omitted.
"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…
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.
If you have a real interest in this area, a subscription to Foreign Affairs would be useful. Especially during the 20th century that's where all these arguments were hashed out. Tactical nukes were already being publicly debated in the 1950s. You may be able to access many older articles, from Foreign Affairs and others, through a free JSTOR account.