California Code, Elections Code - ELEC § 9162

(a) The board of supervisors or any member or members of the board, or an individual voter who is eligible to vote on the measure, or bona fide association of citizens, or a combination of these voters and associations may file a written argument for or against any county measure.An argument shall not exceed 300 words in length. The county elections official shall cause an argument for and an argument against the measure, and the analysis of the measure, to be printed, and shall enclose a copy of both arguments preceded by the analysis with each county voter information guide. The printed arguments and the analysis are “official matter” within the meaning of Section 13303.

(b) The following statement shall be printed on the front cover, or if none, on the heading of the first page, of the printed arguments:

“Arguments in support of or in opposition to the proposed laws are the opinions of the authors.”

(c) Printed arguments submitted to voters in accordance with this section shall be titled either “Argument In Favor Of Measure ____” or “Argument Against Measure ____,” accordingly, the blank spaces being filled in only with the letter or number, if any, which designates the measure. At the discretion of the county elections official, the word “Proposition” may be substituted for the word “Measure” in the titles. Words used in the title shall not be counted when determining the length of an argument.