To discover how much of our resources must be mobilized for war, we must first examine our political aim and that of the enemy. We must gauge the strength and situation of the opposite state. We must gauge the character and abilities of its government and people and do the same in regard to our own. Finally, we must evaluate the political sympathies of other states and the effect the war may have on them.
Carl von Clausewitz[The cause of inaction in war] ... is the imperfection of human perception and judgment which is more pronounced in war than anywhere else. We hardly know accurately our own situation at any particular moment while the enemy's, which is concealed from us, must be deduced from very little evidence.
Carl von Clausewitz