S.C. Code § 7-11-210
Every candidate for selection as a nominee of any political party for any state office, United States Senator, member of Congress, or solicitor, to be voted for in any party primary election or political party convention, shall file with and place in the possession of the appropriate election commission, pursuant to Section 7-11-15 by twelve o'clock noon on March thirtieth a party pledge in the following form, the blanks being properly filled in and the party pledge signed by the candidate: "I hereby file my notice as a candidate for the nomination as __________ in the primary election or convention to be held on __________. I affiliate with the __________ Party, and I hereby pledge myself to abide by the results of the primary or convention. I shall not authorize my name to be placed on the general election ballot by petition and will not offer or campaign as a write-in candidate for this office or any other office for which the party has a nominee. I authorize the issuance of an injunction upon ex parte application by the party chairman, as provided by law, should I violate this pledge by offering or campaigning in the ensuing general election for election to this office or any other office for which a nominee has been elected in the party primary election, unless the nominee for the office has become deceased or otherwise disqualified for election in the ensuing general election. I hereby affirm that I meet, or will meet by the time of the general or special election, or as otherwise required by law, the qualifications for this office".
Every candidate for selection in a primary election as the nominee of any political party for member of the Senate, member of the House of Representatives, and all county and township offices shall file with and place in the possession of the county board of voter registration and elections of the county in which they reside by twelve o'clock noon on March thirtieth a like party pledge.
The party pledge required by this section to be filed by a candidate in a primary must be signed personally by the candidate, and the signature of the candidate must be signed in the presence of an individual authorized by the election commission director. Any party pledge of any candidate signed by an agent on behalf of a candidate shall not be valid.
In the event that a person who was defeated as a candidate for nomination to an office in a party's primary election shall thereafter offer or campaign as a candidate against any nominee for election to any office in the ensuing general election, the state chairman of the party which held the primary (if the office involved is one voted for in the general election by the electors of more than one county), or the county chairman of the party which held the primary (in the case of all other offices), shall forthwith institute an action in a court of competent jurisdiction for an order enjoining the person from so offering or campaigning in the general election, and the court is hereby empowered upon proof of these facts to issue an order.
S.C. Code § 7-11-210
2013 Act No. 61, Section 14, provides as follows:
"SECTION 14. This act takes effect upon preclearance approval by the United States Department of Justice or approval by a declaratory judgment issued by the United States District Court for the District of Columbia, whichever occurs first."
The amendment by 2013 Act No. 61 became effective June 25, 2013, see South Carolina Libertarian Party v. South Carolina State Election Com'n, 407 S.C. 612, 757 S.E.2d 707 (2014).