The above number for costs incurred since the policy has been in place—ten years, as of the most recent data we have to work with—comes from a study by a University of California Blue Ribbon Commission (not just blue-state ideologues: check out the military and service academy members). The panel did a simple analysis, with what seem like due caveats, of the direct costs of discharges and the predicted losses from the forgone service of those discharged—plus some fact-checking of GAO numbers that looked suspiciously cooked (though that aspect they treated softly and with some irony).
The panel, of course, made a few assumptions that were not value neutral. They failed to note the policy’s benefits: vastly increased morale among straight service members who, because of the policy, know conclusively that any gay companions are closeted. Also costed at zero, and hard to quantify, were the pain and suffering caused to people deprived of the chance to take astonishing risks for their country because of whom they liked knocking boots with.
Finally, and more seriously, none of this takes into account the possibility that, with recruitment now scraping the bottom of medical and intellectual barrels, some of these recruits simply can’t be “replaced” at the cost that it originally cost to train them.