k71021, I've never heard of it put in those terms, and in fact I think it would be fairly difficult to quantify. Obviously we have a large presence in the middle east, (larger in the last few years) and someone somewhere in the Army could probably give us the total cost of that presence in salary, consumables (bullets, food, etc), depreciation (how many years can you drive a hummer in the desert before it is worn out?) etc. Then divide that by the number of gallons of gas we import from the middle east, but even that wouldn't be a really accurate number.

The military expenditure is done in order to keep supply available, which keeps prices down. So saying how much of the gas price is paying the army isn't really a valid question. The answer is probably "none". I think most gas taxes are for local governments and mostly for highway department budgets and stuff.