May a legislator attend and participate in a rally in the capitol rotunda in support of a pending ballot measure?

Yes.  It is not a violation of RCW 42.52.180 for a legislator to take part in a rally in support of a pending ballot measure if the rally takes place in a public part of the campus which is open to all, on an equal access basis, for expression for or against a ballot measure. There were no facts to suggest that legislative resources such as staff or materials were used to support the Respondent's presentation at the rally.   Rally proponents had obtained the necessary state permits to hold the rally.  Dismissed for lack of reasonable cause.  Allegations of assault committed by Respondent at the rally dismissed for lack of jurisdiction.