What Trump said does logically follow. If SCOTUS strikes down Roe v. Wade and state legislatures outlaw abortion, abortion becomes a crime. Of course, the laws could be written in such a way as to punish only the doctors who perform abortions or some other subset of the people involved in the actual act. But he was merely articulating the principle that crime should be punished.

This reminds me of the inconsistency inherent in the position of people who say they are pro-life "with exceptions." If a fetus is a human being, then deliberately killing it is wrong, regardless of the circumstances of of its conception. The Catholic church, at least, is consistent on this point--its position is that deliberately ending a life is wrong, period. (That includes capital punishment and euthanasia.)

The Catholic position on abortion isn't one I agree with, but, as I say, it's logical. And in this case, so is Trump.