Most theoretic models of multiparty electoral competition make the
assumption that party leaders are motivated to maximize their
vote share or seat share. In plurality-rule systems this is a sensible
assumption. However, in proportional representation systems, this
assumption is questionable since the ability to make public policy is
not strictly increasing in vote shares or seat shares. We present a
theoretic model in which party leaders choose electoral declarations
with an eye toward the expected policy outcome of the coalition
bargaining game induced by the party declarations and the parties'
beliefs about citizens' voting behavior. To test this model, we turn
to data from the 1989 Dutch parliamentary election. We use Markov
chain Monte Carlo methods to estimate the parties' beliefs about mass
voting behavior and to average over measurement uncertainty and
missing data. Due to the complexity of the parties' objective
functions and the uncertainty in objective function estimates,
equilibria are found numerically. Unlike previous models of
multiparty electoral competition, the equilibrium results are
consistent with the empirical declarations of the four major Dutch
parties.