the proper answer is, of course,"i agree with you whole heartedly, and i am sure i could do your job as well as you, so, i'll ship you out on the next peace keeping mission, to work on the front line, and i will fill your seat, and take over your responsibilities, after all, you're just as fungible as the next guy, right? "

(you can bet your ass, he doesn't consider himself fungible!)

i remember where i learned this word-- in a NewYorker 'lawyer' cartoon.. a gentlemen of a certain age, was explaining to an over burdened young man, the "partners are forever, and clerks are fungible"

No doubt in my mind that Mr Rumsfield sees the 20,000 men and women in the front line engagement to be fungible --and he was rude enough to articulate it!