(re: political credibility) -- Ehhh, let’s say you become a doctor because you think healthcare is important. You want to help people and by being a doctor, you hope to have the status to advocate politically for expanding access to healthcare. I don’t see how your authority is impugned because of your desire for advocacy. I think what you’re going for is the loss of authority if you have an ulterior motive that cuts against the stated motive—e.g. if you join a church for political gain but don’t believe in god. As a kidney donor, though, your desire to give and desire to change policy are aligned.
(re: political credibility) -- Ehhh, let’s say you become a doctor because you think healthcare is important. You want to help people and by being a doctor, you hope to have the status to advocate politically for expanding access to healthcare. I don’t see how your authority is impugned because of your desire for advocacy. I think what you’re going for is the loss of authority if you have an ulterior motive that cuts against the stated motive—e.g. if you join a church for political gain but don’t believe in god. As a kidney donor, though, your desire to give and desire to change policy are aligned.