According to the principle of alternative possibilities (PAP), a person is morally responsible for what he has done only if he could have done otherwise. Widerker (Philosophical Perspectives 14: 181-201, 2000) offers an intriguing argument for PAP as it applies to moral blameworthiness. His argument is known as the “What-should-he-have-done defense” of PAP or the “W-defense” for short. In a recent article, Capes (Philosophical Studies 150: 61-77, 2010) attacks Widerker’s argument by rejecting the central premise on which it rests, namely, the premise that a person is blameworthy for his action only if in the circumstances it would be morally reasonable to expect him not to have acted as he did. In this paper, I show that Capes’ criticism does not undermine this premise and, to this extent, Widerker’s argument is safe from Capes’ attack.