Conservative Supreme Court justices have demonstrated a desire to reverse prior decisions on abortion rights. The question, with Chief Justice John Roberts no longer the undisputed swing vote on abortion, is when and how far at least five justices will go to overturn rulings that support a constitutional right to end a pregnancy.Conservative Supreme Court justices have demonstrated a desire to reverse prior decisions on abortion rights. The question, with Chief Justice John Roberts no longer the undisputed swing vote on abortion, is when and how far at least five justices will go to overturn rulings that support a constitutional right to end a pregnancy.