“…In this case we generate synthetic versions of Arizona and Maine from the pool of states that did not implement state legislative public financing programs during this period. 27 We use the following covariates in the construction of the synthetic cases from states without public financing (data sources in parentheses): the average distance between any two legislators (a "party-free" measure of polarization, see Shor and McCarty 2011), state citizen ideology, state citizen ideological extremity, and state government ideology (Berry et al 1998), legislative professionalism (Squire 2007), US Census data on state income, unemployment, population, population density, amount of federal grants, and gross state product (Keele, Malhotra, and McCubbins 2013), and indicators for divided government, Democratic party control, closed-primary states, regions, and term limits. 28…”