"the successful use of tactical nukes against US troops would have encouraged both third-world countries and insurgent forces all over the world to ally themsel

"the successful use of tactical nukes against US troops would have encouraged both third-world countries and insurgent forces all over the world to ally themselves with the Communists to obtain weapons of their own," Such countries are well aware that these weapons exist, and that the Russians can field them anyhow. The more likely response against anyone, at any time using nukes of any size against the US is that they 'wake the dragon' in a way bigger than Pearl Harbour. Remember the 'fear' of nukes is quite substantial, even if tactical nukes are a small deal, the concern is big. It would have been 9/11 x 10. And the world would be different today probably.