SDB writes that pipsqueek nations with nukes could deter the US from attacking them by threatening to sneak a nuke into one of our cities. But wouldn't the very act of making such a threat trigger an all-out nuclear attack by America against them? That's the guiding principle behind the policies of Mutually Assured Destruction and nuclear deterrence.
If a nuclear-armed pipsqueak nation saw indications that we were seriously contemplating such an attack, or saw us actually begin such a buildup, they'd either privately or publicly threaten us with massive consequences unless we backed down. They wouldn't threaten our troops; they'd threaten our cities.Our only options would be to back down, or to go nuclear immediately. If we're still following MAD, we'd choose the second option. The point of MAD is to prevent any nation from blackmailing us with the threat of nuclear attack, and forces them to either just do it or keep their mouth shut.