I think you could include rules on disclosure by political parties and others on use. The worst possible case was that of Cambridge Analytica, a company that authored certain practices aimed at influencing voters. If political parties were subject to privacy laws and these practices continued to be used, at least penalties could be imposed on those who obtain this type of information. There's a whole range of consequences.
Rules on the protection of information—that is to say security mechanisms—could also be included. These issues are currently the subject of voluntary measures on the part of political parties. If the parties were subject to the laws, there would be legal consequences for not protecting the information properly.