No man can serve two masters

Both the classic mass party model of democracy and the more recent Downsian model initially appear consistent with the same, simple, principal–agent model of democratic party government. Once party is disaggregated into its ‘three faces’, however, the models are shown to be quite different. And once intra-party democracy is imposed on the Downsian model, or the idea that parties compete for unattached voters rather than each simply mobilizing its classe gardée is imposed on the mass party model, the simplicity of the original principal–agent model breaks down, with the party in public office forced to serve two masters with competing objectives and making incompatible demands. The result is to highlight both the complexity of democratic government and the limitations of principal–agent models in explaining it.