  We present an equilibrium model of politics in which political platforms
compete over public opinion. A platform consists of a policy, a coalition of
social groups with diverse intrinsic attitudes to policies, and a narrative. We
conceptualize narratives as subjective models that attribute a commonly valued
outcome to (potentially spurious) postulated causes. When quantified against
empirical observations, these models generate a shared belief among coalition
members over the outcome as a function of its postulated causes. The intensity
of this belief and the members' intrinsic attitudes to the policy determine the
strength of the coalition's mobilization. Only platforms that generate maximal
mobilization prevail in equilibrium. Our equilibrium characterization
demonstrates how false narratives can be detrimental for the common good, and
how political fragmentation leads to their proliferation. The false narratives
that emerge in equilibrium attribute good outcomes to the exclusion of social
groups from ruling coalitions.
