Since this thread has been well and truly derailed, might as well jump in feet first.
Your question is invalid since you don't use nukes except against large immoveable targets. That's why they are generally referred to as 'strategic' weapons. Iraq and Afghanistan are not wars in the conventional nation-state sense. They are guerrilla wars.
From http://www.britannica.com/EBchecked/topic/568246/strategic-weapons-system
any weapons system designed to strike an enemy at the source of his military, economic, or political power. In practice, this means destroying a nation’s cities, factories, military bases, transportation and communications infrastructure, and seat of government. Strategic weapons systems use atomic or thermonuclear devices, because only these weapons have sufficient explosive power to destroy, with relative ease and quickness, the entire war-making capability of a large nation.
Not a peep about guerrilla warfare in there.
That's where 'tactical' weapons come in.
From http://www.britannica.com/EBchecked/topic/580079/tactical-weapons-system
system integrating tactical weapons with electronic equipment for target acquisition, aiming, or fire control or a combination of such purposes. Tactical weapons are designed for offensive or defensive use at relatively short range with relatively immediate consequences. They include weapons used for antitank assault, antiaircraft defense, battlefield support, aerial combat, or naval combat.
Unlike strategic weapons systems, which are operated by only a handful of nations, tactical weapons systems are ubiquitous: in one version or another they are manufactured by at least 15 countries, and in one form or another they occur in virtually every country that has an army, navy, air force, or guerrilla or terrorist organization of any consequence. They are generally classified according to their point of launching (surface or air) and their target location (also surface or air).
BTW, WWII was ended by nukes, yes. But that was only the period ending a very long sentence. What oldsaw is referring to was the 'will to win' which came from the grassroots of the US population and was permeated through the military, in essence: dammit we are here to win so let's win. Don't worry about the reasons why we are there, push the enemy back and do NOT let them have a safe haven.
Vietnam was run as a farce, it's well documented that in many cases once a hill was taken (you always go for the high ground) it was abandoned and the Cong would take back over, thus wasting US blood and treasure. I feel for the poor bastards who watched their buddies die for basically nothing. In that way it was completely unlike WWII. I hope like hell that's not happening in Iraq and Afghanistan.
So we have a guerrilla war going on.
http://www.britannica.com/EBchecked/topic/248336/guerrilla
member of an irregular military force fighting small-scale, limited actions, in concert with an overall political-military strategy, against conventional military forces. Guerrilla tactics involve constantly shifting attack operations and include the use of sabotage and terrorism.
In a guerrilla war if someone points a weapon at you, you don't ask questions, you simply vaporize them on the spot. 
The real problem, as you said, is a small scattered guerrilla army. Let me ask you this: how would you suggest we deal with such a thing?
