Sorry to come late to this debate, but . . .

Quote Originally Posted by Zenpundit
In WWII, the US spent approximately $ 330 billion 1940 dollars to wage war. By any standard that was a lot of money. However, for that fantastic sum, the US received a considerable strategic and tactical ROI including: contributing to the destruction, defeat and occupation of Nazi Germany, Fascist Italy and Imperial Japan; the deaths of roughly 11 million Axis soldiers and civilians; according to John Keegan, producing enough equipment and munitions to outfit 1200 divisions; thousands of combatant ships; 300,000 planes and three functioning atomic bombs, two of which saw use against the enemy.

Now, taking the lower-end estimate expenditure of $ 1 trillion for the war on terror, how does the ROI today compare to the example of WWII?

We have killed or captured low thousands (less than 10k) Islamist insurgents, some of who are al Qaida (President Bush claimed 75 % of AQ leadership) but AQ has held out against the US more than twice as long as the Wehrmacht and still has refuge in Pakistan. We have occupied Afghanistan and overthrown the Taliban government that hosted AQ, but the Taliban too has a refuge in Pakistan and continues to field fighters in Afghanistan. We invaded and occupied Iraq and needed a prolonged campaign to pacify the country and managed to exterminate an AQ affiliate there ( that only appeared because of our invasion). We have circumscribed AQ's operational capacity but from 2001-2010, the group has still managed to sporadically sponsor/inspire significant acts of terrorism in allied countries.
It might be worth comparing apples to apples. The two efforts are of completely different kinds in oh so many fundamental ways. As a simple example consider constancy of purpose in the two conflicts (and that is problematic because OIF and OEF are, and were, not one conflict.) From the Allies’ perspective, World War II had a fairly constant scope. I do not think the same can be said for the efforts now categorized as overseas contingency operations in the CENTCOM AOR. When scope and requirements are not defined early and held constant, then the cost of execution rises significantly. Don’t just take my word for it; take a look at most Defense acquisition programs.
Quote Originally Posted by Zenpundit
There are significant potential costs to not having big forces. Agreed. I am not interested in having a military that cannot operate large units.
That said, using big units where smaller ones work with greater efficiency and effectiveness is a poor tactical choice.
It is a poor strategic choice if you cannot afford to deploy large units in order to use them inefficiently for years on end. This too is a significant cost - a threat actually - to our overall military capabilities
We can have big units and use them where/when big units work best and select more appropriate tools or degrees of force for other tasks, husbanding our resources for larger problems when they come along.

. . .

You can only fight to the degree and for so long as you can afford to pay for the kind of fighting that you are doing. Different kinds of fighting incurs (sic) different sets of costs. Paying enormous costs for marginal strategic results is not "winning". Ignoring fundamental economic trade-offs in selecting military tactics and operational approaches is simply stupid. This is not an argument for doing nothing, but to do it with eyes open and with a long-term perspective.
The assertions made in this second set of quotations have no basis. Where is the double blind test that shows that small units do better than “big battalions” in a given operational scenario? Comparing the effort from the initial days of OEF in Afghanistan with how things happen to be proceeding on the ground today is another example of comparing apples to oranges. The thinking expressed in this combined quotation is similar to the stuff that Bentham and Mill used to justify Utilitarianism as a moral theory. One sets a problem that is impossible of solution when one tries to justify a decision by comparing its consequences to the hypothetical consequences of a decision not made or a course of action not taken. One cannot turn back the hands of time, replay the tape, and choose a different path. One can say that a given action produced more happiness, greater cost benefit, etc. than another that was not chosen but that is because the act not chosen, being unchosen, produced nothing. But, that is really the degenerate case.