The Chairman Speaks
PACE: It is absolutely responsibility of every U.S. service member if they see inhumane treatment being conducted, to intervene, to stop it.
RUMSFELD: I don't think you mean they have an obligation to physically stop it, it's to report it.
PACE: If they are physically present when inhumane treatment is taking place, sir, they have an obligation to try to stop it."

Colonel W. Patrick Lang is a retired senior officer of U.S. Military Intelligence and U.S. Army Special Forces (The Green Berets). His blog is a wonderful source of military history and commentary.