After briefly sketching common-morality principlism, as presented in Principles of Biomedical Ethics, this paper responds to two recent sets of challenges to this framework. The first challenge claims that medical ethics is autonomous and unique and thus not a form of, or justified or guided by, a common morality or by any external morality or moral theory. The second challenge denies that there is a common morality and insists that futile efforts to develop common-morality approaches to bioethics limit diversity and (...) prevent needed moral change. This paper argues that these two critiques fundamentally fail because they significantly misunderstand their target and because their proposed alternatives have major deficiencies and encounter insurmountable problems. (shrink)