Who can decide?

The constitutionally provided "right of self-determination" can be lost when a individual's mental "capacity to choose" is affected by medical or psychiatric illness. "Competency" is a court-determined definition. However, physicians are expected to know how to determine "capacity to choose". This medical responsibility has become clear in the light of recent United States Supreme Court and South Dakota legislative action. The complexity of this issue is discussed, and a testing method for "capacity" is described.