David Cole, writing about the role of designers in a very good presentation from last year.
If the project you were working on failed — it hit the market and nobody wanted it, nobody used it — would you blame yourself? If the answer is no, then I think you don't have enough authority. If you're blaming others for the outcomes in your work, it's time to demand more.
I would generalize this statement to all professions, all roles. I would also add that responsibility is key to this equation as well, and that responsibility isn't given - it's taken.