Dave in Texas mentioned that he found the Tables of Organization and Equipment (TO&E) for Army units interesting. A TO&E sets the standard way a particular unit is organized by defining the chain of command, showing how many people in what pay-grades and specialties they get, and what types of equipment the unit will have. An actual TO&E is a huge document, but in casual use, it is a fancy way of saying org-chart.
No commander ever has all the assets that he wants to complete his mission. For instance, in our Light Division, we’ve got nine infantry battalions in three brigades, but only one engineer battalion. The Division Commander must decide where to focus the engineering effort. Will all the engineer support go to just one battalion? Or just one brigade? Or will he spread the effort around, giving everyone a taste of the pie, but leaving many tasks undone at each location? Generally, a commander will devote the majority of an asset to one subordinate, with a set of priorities that he wants accomplished. For instance, for a division in the defense, with two brigades on the line, and the third in reserve, the brigade most likely to be attacked would receive the bulk of the engineering assets to set up obstacles and to improve the defenses. Time permitting, the assets would then shift to the other forward brigade, and finally, to the reserve brigade.
While this may be the norm, it isn’t set in stone. Leaders at all levels must use their experience, judgement and estimation of the situation to make decisions on which allocation of assets will best achieve the objective. He may well decide that only one brigade is likely to receive the enemy’s attack and direct all engineer efforts to that brigade, leaving the other two to fend for themselves. Obviously, the proper allocation of limited resources will have a huge effect on the organizations success.