Any incumbent justice of the supreme court may become a candidate for re-election as a justice of the supreme court by filing with the secretary of state an affidavit of candidacy not less than 180 days prior to the expiration of his term of office.

     The affidavit of candidacy shall contain statements that the affiant is an incumbent supreme court justice, that he is domiciled within the state, that he will not have attained the age of 70 years prior to the date of election and a declaration that he is a candidate for election to the office of supreme court justice.