As far as the physical application of Aikido, I believe that first and foremost that your safety, that of your family, friends, and the innocent are deserving of the most protection. After that.................. comes the well-being of the attacker/s. I believe that using only the amount of force necessary to end the confrontation/attack is appropriate, ethical and an ideal to strive for. However, being pragmatic, that can mean a few different things. Some believe as I infer from you post, that as Aikidoka we are under an "implied" obligation to do so, but there are different means to arrive at this desired place. Some, quoting Osensei in his later years (Like Yoda--when his focus had changed from being martially dominant to a more philosophical/spiritual focus) that one should treat an attacker like an "out of control child".