It should be left up to the states. (See: Amendment X, Constitution of the United States of America)
Amendment V states in part: ...nor be deprived of life, liberty, or property, without due process of law...
I believe going the State by State route is the most effective but not as a way of saying that it is just a State issue. Protection of individual rights (and none greater than one's own right of existence) is a Federal issue.
However it does not address the question of intrinsic right and wrong. If you were a legislator in one of these states, freed from the Federal restraints of Roe vs Wade, to what extent would you vote to protect unborn babies and pregnant mothers in your state?