S.D. Codified Laws § 3-18-2
Public employees shall have the right to form and join labor or employee organizations, and shall have the right not to form and join such organizations. Public employees shall have the right to designate representatives for the purpose of meeting and negotiating with the governmental agency or representatives designated by it with respect to grievance procedures and conditions of employment and after initial recognition by the employer, it shall be continuous until questioned by the governmental agency, labor or employee organization, or employees, pursuant to § 3-18-5. It is a Class 2 misdemeanor to discharge or otherwise discriminate against an employee for the exercise of such rights, and the governmental agency or its designated representatives shall be required to meet and negotiate with the representatives of the employees at reasonable times in connection with such grievance procedures and conditions of employment. The negotiations by the governmental agency or its designated representatives and the employee organization or its designated representatives shall be conducted in good faith. Such obligation does not compel either party to agree to a proposal or require the making of a concession but shall require a statement of rationale for any position taken by either party in negotiations. It shall be unlawful for any person or group of persons, either directly or indirectly to intimidate or coerce any public employee to join, or refrain from joining, a labor or employee organization.
SDCL 3-18-2