Lincoln's point was there are no distinct words in the Constitution expressing the right of a human to own another human. The Taney Court had to misread the Constitution in order to assert such a "right," which is what the Court did in Roe v. Wade a century later.
If Giuliani believes in a strict construction interpretation of the Constitution, he could not support abortion, because a strict constructionist does not find language permitting it. For him to take the position he does on abortion and then to say he would nominate strict constructionists to the bench twists him and the law into a pretzel.
Giuliani says people who don't like his position do not have to vote for him. Many social conservatives who view abortion as a make or break issue are likely to follow his advice.
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