Tennessee Code Title 2. Elections § 2-13-317

The results of the preferential presidential primary shall be binding on the delegates to the national conventions as provided in this section. The delegates to the national conventions shall be bound by the results of the preferential presidential primary for the first two (2) ballots and shall vote for the candidate to whom they are pledged as provided in § 2-13-307. The delegates shall thereafter be bound to support such candidate so long as the candidate, not to exceed two (2) ballots, has twenty percent (20%) of the total convention vote or until such time the candidate of their party releases them from the results of the presidential preference primary.