It is now widely supposed in many democracies that the modern political campaign needs to be “data driven” to consolidate existing support and to find potential new voters and donors.  The capture of data on political opinions and affiliation permits the construction of profiles on individual voters and the “micro-targeting” of increasingly precise messages to increasingly refined segments of the electorate.  To what extent should modern campaigns be allowed to “know” the electorate?  The answer to this question relies to some extent on privacy and data protection rules, based on principles