“The decision whether or not to terminate a pregnancy is essentially a moral decision and in a free and democratic society, the conscience of the individual must be paramount to that of the state,” O’Connor said. (Source)
The conscience is above the State, but it is not above the natural law. It is not above the moral law which says that no one may murder.
But then again, we know where O’Connor is getting this conscience thing, don’t we?
26. Counsellors may meet others who, accepting the teaching of the Holy Father, find that because of particular circumstances they are involved in what seems to them a clear conflict of duties, e.g., the reconciling of conjugal love and responsible parenthood with the education of children already born or with the health of the mother. In accord with the accepted principles of moral theology, if these persons have tried sincerely but without success to pursue a line of conduct in keeping with the given directives, they may be safely assured that, whoever honestly chooses that course which seems right to him does so in good conscience.