53 (b) failure to obey, uphold or defend this Constitution; (c) wilful violation of this Constitution; (d) inability to perform the functions of the office because of physical or mental incapacity; should be investigated in terms of this section. (2) Upon the passing of a resolution in terms of subsection (1), the Committee on Standing Rules and Orders must appoint a joint committee of the Senate and the National Assembly consisting of nine members reflecting the political composition of Parliament, to investigate the removal from office of the President or Vice-President, as the case may be, from office. (3) If— (a) the joint committee appointed in terms of subsection (2) recommends the removal from office of the President or Vice-President; and (b) the Senate and the National Assembly resolve, by a joint resolution passed by at least two-thirds of their total membership, that the President or -Vice-President, as the case may be, should be removed from office; the President or Vice-President thereupon ceases to hold office. 5.11 Presidential immunity (1) While in office, the President is not liable to civil or criminal proceedings in any court for things done or omitted to be done in his or her personal capacity. (2) Civil or criminal proceedings may be instituted against a former President for things done and omitted to be done before he or she became President or while he or she was President. (3) The running of prescription in relation to any debt or liability of the President arising before or during his or her term of office is suspended while he or she remains in office. (4) In any proceedings brought against a former President for anything done or omitted to be done in his or her official capacity while he or she was President, it is a defence for him or her to prove that the thing was done or omitted in good faith. 5.12 Functions of Vice-Presidents The Vice-Presidents assist the President in the discharge of his or her functions and perform any other functions, including the administration of any Ministry or Act of Parliament, that the President may assign to them. 5.13 Acting President (1) Whenever the President is absent from Zimbabwe or is unable to exercise his or her official functions through illness or any other cause, those functions must be assumed and exercised— (a) by the first Vice-President; (b) where the first Vice-President is unable to exercise those functions, by the second Vice-President; or