This one's not inconsistent with Catholic teaching. The Vatican City itself had the death penalty on the books until 1969, so it's unlikely that all the popes and cardinals up to that point weren't Catholic . . .
I agree that Rudy is trying to square the circle with his absurd position on abortion. If killing children is wrong, then it's goofy to assert someone has a right to "choose" it. If I choose bank-robbery, is Rudy going to back me up?
The brilliant thing about Catholic theology is that it doesn't let you play Three-Card Monte with morality. If you're doing wrong, it just crushes you with the leverage of logic. (See Thomas Aquinas.) Everything has been thought through, and human nature doesn't change.
As I learned once many years ago, never get into an argument with a Jesuit!