Normal and regular conduct of a public office or agency, as that term is used in the proviso to RCW 42.17A.555, means conduct which is (1) lawful, i.e., specifically authorized, either expressly or by necessary implication, in an appropriate enactment, and (2) usual, i.e., not effected or authorized in or by some extraordinary means or manner. No local office or agency may authorize a use of public facilities for the purpose of assisting a candidate's campaign or promoting or opposing a ballot proposition, in the absence of a constitutional, charter, or statutory provision separately authorizing such use.