I have a hypothetical question:
Suppose that someone was running for office who was opposed to killing Jews except when they were mentally ill or very old. Should such a person ever get elected? Could you as a Catholic vote for such a person?
Now suppose that someone was running for office who was opposed to killing the unborn except in cases of rape or incest. Why is this different? Why do we vote for such people and try to pass laws with such exceptions? Why should our bishops allow such politicians to receive Communion? Do you think that an elected Catholic official who advocated a return to the policies of Nazi Germany would be welcomed to Communion? Do you think that the US Bishops' conference would issue a joint statement condemning such an individual's position and possibly excommunicate the person as well? I hope they would but that would be inconsistent with their actions since 1974 when Roe V. Wade was decided.