The Principle of Robust Alternatives (PRA) states that an agent is responsible for doing something only if he/she could have performed a ‘robust’ alternative: another action having a different moral or practical value. Defenders of PRA maintain that it is not refuted by a ‘Frankfurt case’, given that its agent can be seen as having had such an alternativeprovided that we properly qualify that for which she is responsible. I argue here against two versions of this defense. First, I show that those who maintain that a ‘Frankfurt agent’ is responsible forvoluntarily performing his/her action must attach moral significance to his/her luck. I proceed to discuss Carl Ginet's strategy of temporally qualifying ascriptions of responsibility, arguing that his counterexample to the principle that ‘If an agent is responsible for doing A @ t, then he/she is responsible for doing Asimpliciter’ is disanalogous to a Frankfurt case.