Well, assuming that the Army and USMC do lower their standards during times of war when difficult to recruit, you would still have to assume that those lower standards result in a less educated and more underprivileged Army and USMC than their civ cohort. I am guessing that I feel that is less the case than you. But more important is taking a look at who actually sacrifices. So maybe more poor folk enlisted during recent wars because others were not inclinded to and the lower standards cast a wider net. But that doesn't mean those people were more likely to become a casualty. But to go back to my point. It is all volunteer. They don't have to go into the military. They don't have to choose an MOS that is more likely to find them humping a pack in the Hindu Kush. And to expand on your point, would it be so bad that underprivileged people are more inclined to go military when it is generally a valuable experience that can better people in many ways? Clearly their service is a plus for society and it usually is a plus for them as individuals and society again, if it gets them advanced education, better job prospects and the stability of home ownership all before their peers back home.As a result, we disproportionately lose the less educated. If, as I suggested initially, we are drawing deep, as opposed to wide, we are creating something of a permanent "sacrificial class".
I like your term "sacrificial class" but mostly reject it, as I understand your definition. I simply don't think income matters as to who bears the sacrifice. Clearly that is debatable. But I think it is important to expand the debate as I argued above. What does it say about our military and our society that it appears the back bone of our military is from one region of the US, tends to be religious, charitable, civic minded, conservative and from rural and small town America (remember we are talking about proportional representation) ? Only a very small percentage are joining purely because of personal finances. So what motivates those people to join out of proportion to others? Is it the Southern culture? Is it the Judeo Christian values learned by church goers? A political conservatives interest in preserving American from threats they perceive?