S.C. Code § 7-19-80
Each candidate for presidential and vice-presidential elector shall declare which candidate for president and vice-president he will vote for if elected. Those elected shall vote for the president and vice-president candidates for whom they declared. Any person selected to fill a vacancy in the electoral college shall vote for the candidates the elector whose place he is taking had declared for. The declaration shall be made to the Secretary of State on such form as he may require not later than sixty days prior to the general election for electors. No candidate for president and vice-president elector shall have his name placed on the ballot who fails to make such declaration by the prescribed time. Any elector who votes contrary to the provisions of this section shall be deemed guilty of violating the election laws of this State and upon conviction shall be punished according to law. Any registered elector shall have the right to institute proper action to require compliance with the provisions of this section. The Attorney General shall institute criminal action for any violation of the provision of this section. Provided, the executive committee of the party from which an elector of the electoral college was elected may relieve the elector from the obligation to vote for a specific candidate when, in its judgment, circumstances shall have arisen which, in the opinion of the committee, it would not be in the best interest of the State for the elector to cast his ballot for such a candidate.
S.C. Code § 7-19-80