Sec. 15. A governing body may not dismiss, suspend, or enforce a mandatory leave of absence on a teacher who is a candidate for public office unless evidence is submitted to the governing body that would substantiate a finding that the teacher's activity has:
(1) impaired the teacher's effectiveness in the teacher's service; or
(2) interfered with the performance of the teacher's contractual obligations.
A suspension is valid only during the period of the impairing activity.