"For the Greater Good": Part I

I watched "Law and Order: Criminal Intent" last night, and was struck by one of the detectives on the show using the phrase, "the greater good." In the context of the episode, the detective is haranguing a veteran of the war in Iraq to turn in his guilty father with, "The greater good. That's the oath you took. It's the same as the oath I took. The greater good." The phrase struck a chord in me. It helped me to put my finger on an attitude, one might even say an ethos that has been growing in its aura ever since 9/11. I decided that before I wrote down my thoughts on this phrase, however, I would "google it." Nowhere could I find any reference to the phrase as a part of an oath taken by either the military or the police. I had no better luck tracking down the origin of the phrase. I got hits that related to the Hippocratic Oath and to the related phrase, "lesser of two evils," but even a dip into Bartlett's quotations revealed nothing. Perhaps I should write to the creators of "Criminal Intent" to determine what the basis for Chris Nolte's line is. In spite of my failure to find, shall we say, a scholarly reference, I feel I don't want to let escape the opportunity to set down my feelings about what the phrase conjures up in me at this historical moment. Any leads on its origins would be appreciated.