Tennessee is a Right to Work State. Employees who work in Tennessee, except on federal property or for a railway or airline, have a right to resign from union membership and not pay union dues or fees.

Tenn. Code Ann. §§ 50-1-201 through 204
§ 50-1-201. Denial of employment because of affiliation or nonaffiliation with labor union.
It shall be unlawful for any person, firm, corporation or association of any kind to deny or attempt to deny employment to any person by reason of such person's membership in, affiliation with, resignation from, or refusal to join or affiliate with any labor union or employee organization of any kind. (Enacted 1947.)

§ 50-1-202. Contracting for exclusion from employment because of affiliation or nonaffiliation with labor union.
It shall be unlawful for any person, firm, corporation or association of any kind to enter into any contract, combination or agreement, written or oral, providing for exclusion from employment of any person because of membership in, affiliation with, resignation from, or refusal to join or affiliate with any labor union or employee organization of any kind. (Enacted 1947.)

§ 50-1-203. Exclusion from employment for payment of or failure to pay union dues.
It shall be unlawful for any person, firm, corporation or association of any kind to exclude from employment any person by reason of such person's payment of or failure to pay dues, fees, assessments, or other charges to any labor union or employee organization of any kind. (Enacted 1947.)

§ 50-1-204. Penalty.
(a) Any person, firm, corporation, or association of any kind violating any of the provisions of this part commits a Class A misdemeanor.
(b) Each day that any person, firm, corporation or association of any kind remains in violation of any of the provisions of this part is deemed to be a separate and distinct offense, punishable in accordance with the provisions of this section. (Enacted 1947.)