(1)    A local governmental unit, as defined in s. 66.0135 (1) (c), may grant a leave of absence to any employee or officer who is inducted or who enlists in the U.S. armed forces for a period of federal active duty of not more than 5 years unless the employee is involuntarily retained for a longer period. No salary or compensation of the employee or officer shall be paid, nor claim for the salary or compensation exist, during the leave of absence, except as provided in this section. If the employee’s or officer’s salary or compensation is less in the U.S. armed forces than was paid by the local governmental unit, that governmental unit may pay the employee or officer the difference between the salary or compensation paid by the U.S. armed forces and the salary or compensation that the employee or officer was paid by the local governmental unit at the time that he or she enlisted in or was inducted into the U.S. armed forces.

   (2)   The local governmental unit may provide for safeguarding the reinstatement and pension rights, as limited in this section, of any employee or officer so inducted or enlisted.

   (3)   No employee or officer who is appointed to fill the place of any employee or officer so inducted or enlisted shall acquire permanent tenure during the period of the replacement service.

   (4)   If the leave of absence under sub. (1) is granted to an elected or appointed official or employee and the official or employee has begun federal active duty, a temporary vacancy exists and a successor may be appointed to fill the unexpired term of the official or employee, or until the official or employee returns and files an election to resume the office if the date of the filing is prior to the expiration of the term. The appointment shall be made in the manner provided for the filling of vacancies caused by death, resignation, or otherwise, except that no election need be held to fill a temporary vacancy. The appointee has all the powers, duties, liabilities, and responsibilities and shall be paid and receive the compensation and other benefits of the office or position, unless otherwise provided by the local governmental unit. Within 40 days after the termination of federal active duty, the elected or appointed official or employee, upon filing with the clerk of the local governmental unit, a statement under oath of termination and that the official or employee elects to resume the office or position, may resume the office or position for the remainder of the term for which elected or appointed. The person temporarily filling the vacancy shall cease to hold the office on the date of the filing.