The 9 to one is actually kind of low by today's standard. The service tail has gotten longer. The numbers you throw out are pretty accurate. I read a book called Killing Zone. This was just after a large downsizing of the army. The author lamented the death of shooters in the service. The numbers he gave were around 100,000 shooters that are combat infantry from all services.
Squads in the US Army were reduced to 9, the Marines kept theirs at 12. A platoon then is X3 or 27 and 36 adding officers. Platoon up to 44 or 3-4 squad's three infantry maybe a weapons squad. Company up to 190 maybe more with 3-5 platoons. Battalion up to 1000, but more like 900. So doing the math we have only about 100 infantry battalions' worth of trained frontline shooters.
Now you get into the Pentagon's slight of hand. In Iraq, they are civilianizing a lot of support jobs so that the tooth to tail is shorter. Remember Halliburton and KBR? Instead of having Troopers driving the new red ball express, they are paying civilian truck drivers 6 figures to do it and in some instances die for it.
But the tail is still long. I can't find the numbers, but look at the formations deployed from the reserves and national guard. Most if not all are support units. Another dilemma is that even support troops are exposed to situations where they are in combat. So they are trying to make them eligible for a new type of CIB or combat infantrymen's badge. One that doesn't say, I am a combat infantry man, but rather, I have been in combat. The bottom line is even the pentagon is having trouble sorting the tooth to tail numbers out.
Most of the time in these days, the word infantry is rare and because of the changing orders of battle for every country, can be confusing, for example, the u.s.m.c doesn't regard its troops as infantry but rather marines. Infantry is more to signify man power present in battle or on soil to make the count, as for them being rifleman that depends on the setup of the brigade or regiment. so if the current count of u.s forces in Iraq is 140,000. about 50-60 thousand would be combatants and the rest would fit into medics, engineers, tech support, artillery and armor and logistical. Including the airborne wings of the army and marine core.
The answer you require is elusive because of the new U.S. Army's UA or Unit of Action, which will replace the brigade. In other words, the UA (more specifically "grunts") is oriented to the specific mission that it will be assigned. For example, a UA that is ordered to perform a humanitarian mission would be configured then one that was ordered to perform a combat mission.
It's all about flexibility. In the military you know that whoever is around you is all the friend that you got.
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