I wonder if Cain didn't pull something brilliant here. Maybe it was just a gaffe and a recovery. In fact, I think it was. But look at the result. Upon digging into his position with the mere scratch of a fingernail one can see that he is 100% pro-life, unequivocally. So much so, that he doesn't even go for the middling "except in cases of rape or incest" equivocation.
But the effect of what he's done here is to affirm life and his position on it, as well as making a commentary on his view of the power of the presidency and the office's ability to affect policy regarding abortion. It's NOT the president's job to tell people what to do in their personal lives, and these ARE decisions that families make on their own. Those are realities. He can simultaneously hold those realities, and say that if legislation came to his desk outlawing abortion in all 50 states, he would sign it.
For those looking for a pro-life president, they will see one. For those looking for a president who doesn't seek to interfere in their personal decisions, they will see one. For those looking for a president who understands the constitutional limits of the office, they will see one. Through the dust-up, he reaffirmed his pro-life credentials, while taking away some of the threat some "middle-of-the-roaders" might find in a zealous pro-life candidate.
Brilliant, or lucky? Or am I over-analyzing?