This Article argues that the defense attorney has a multifaceted fiduciary duty toward the client with mental disability. That duty requires, first and foremost, respect for the autonomy of the client. The lawyer shows that respect not only by heeding the wishes of the competent client but by refusing to heed the wishes of the incompetent client. A coherent approach to the competency construct is therefore important. Following the lead of Professor Bonnie, this Article has broken competency into two components: assistance competency and decisional competency. It has defined the former concept in traditional terms, as an understanding of the criminal process and an ability to communicate relevant information, while arguing that the latter concept should be defined in terms of basic rationality and self-regard.