Health,
I am not sure if you are understanding what I am writing. Halachically, for Jews, there are many circumstances (including within 40 days of conception which I think would apply to non-Jews as well) in which abortion may be permitted (and some where it is required) according to many poskim. A federal law banning abortion except in life-threatening would apply nationally and would effect the Jewish population in every state. I would not want the Jews to be prevented from the option of an abortion in situations where it would be mutar.
Therefore, giving the issue back to the States to decide would be the best solution. If, chas v’shalom, someone was in a situation where they needed an abortion, they could always travel to one of the lenient states.