In this rather random and novice study of Sun Tzu's "The Art of War," let's start with these passages from chapter two:
A protracted battle will blunt weapons and dampen ardor.
If troops lay siege to a walled city, their strength will be exhausted.
If the army is exposed to a prolonged campaign, the nation's resources will not suffice.
When weapons are blunted, and ardor dampened, strength exhausted, and resources depleted, the neighboring rulers will take advantage of these complications.
Then even the wisest of counsels would not be able to avert the consequences that must ensue.
Therefore, I have heard of military campaigns that were clumsy but swift, but I have never seen military campaigns that were skilled but protracted.
No nation has ever benefited from protracted warfare.
Therefore, if one is not fully cognizant of the dangers inherent in doing battle, one cannot fully know the benefits of doing battle.
Those skilled in doing battle do not raise troops twice, or transport provisions three times.
Toward the very end of the chapter, this passage appears that sums it all up:
The military values victory. It does not value prolonging.
We've had troops in Iraq for going on four years. Isn't it time to git 'er done?
No more backing away from cities like Fallujah in 2004. No more allowing Muqtada al Sadr to run around free.
If we don't do it now, when is it going to be any less difficult?