Party-bosses vs. party-primaries: Quality of legislature under different selectorates

We compare the legislature quality under an exclusive, centralized selectorate (such as a party-principal) with that under an inclusive, decentralized selectorate (such as a party-primary). In our model, two parties compete over three districts: two are home districts of each party while the third is a battleground district characterized by weaker and uncertain policy preferences. We find that when home districts are “safe,” and the parties' candidate pools are of comparable quality, an equilibrium legislature under party-primaries is always of higher quality than an equilibrium legislature under party-principals. When we extend the model to include a general number of districts with candidates of only high or low quality, we show that, as long as there are not too few nor too many highest-quality candidates, party-primaries still perform better than party-principals.