Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We analyze two-party electoral competition with a one-dimensional policy space, costly policy changes, and random negative shocks to a party's viability over an infinite horizon. We show the existence and uniqueness of stationary Markov perfect equilibria in which parties use so-called simple strategies. Regardless of the initial policy, party choices converge in the long run to a stochastic alternation between two policies, with transitions occurring if and only if parties suffer a negative shock to their viability. Although costs of change have a moderating effect on policies, full convergence to the median voter position does not take place when parties are polarized.