Using data on income shares of the highest earners, available for most of the 20<sup>th</sup> century for many countries, Scheve and Stasavage (2007) present substantial contrary evidence on the effects of partisanship. Though their focus is not on these partisan effects, _per se_ , they find that the association of partisanship and inequality disappears over longer time periods. We follow most of the literature in using LIS-style survey data, but for many more countries. In addition, though, we bring into the analysis temporal variables – party and democratic age – that are relevant to the issues raised in Scheve and Stasavage (2007).<sup>2</sup> Even if the interests of the poor are represented by left-wing parties, left-wing parties differ in their incentives to pursue the redistributive agenda. Becher (2014) re-examines an argument that emerges from Iversen and Soskice (2006), that the middle classes oppose left-wing parties in majoritarian systems because these parties cannot credibly commit to moderate their stance on redistribution. He observes that they can, in fact, make such a credible commitment, as long as the cost of identifying and nominating moderate candidates is not too great. By nominating moderate candidates (e.g., candidates who are not members of labor unions), left-wing parties bind themselves to a redistributive agenda that is more appealing to middle class voters.

We extend these lines of research with three related arguments. First, commitment strategies, including the nomination of moderate candidates, require a high degree of party organization. Second, left-wing parties that can make credible commitments are likely to advocate lower levels of redistribution. Third, older parties are more likely to exhibit the organization necessary to make credible commitments than younger parties.

Parties’ ability to credibly commit to any particular program depends on whether party leaders can curb free-riding by party candidates (e.g., unilateral departures by candidates from the party program); and whether party members can limit shirking by leaders (e.g., insufficient attention to the programmatic image of the party) (Keefer, forthcoming). These activities require a high level of party organization, however. For example, the recruitment and vetting of candidates emphasized by Becher (2014) requires significant effort that officials are more likely to undertake if the party organization rewards them for it. Moreover, the way parties are organized itself generates information about candidates. As Becher (2014) points out, party officials learn about candidate characteristics by observing how candidates perform various functions in the party.

Becher’s (2014) argument is that left-wing parties seeking to appeal to the middle class choose moderate candidates in order to credibly commit to lower levels of redistribution. In their analysis of populism, Acemoglu, Egorov and Sonin (2011) point to another threat to credibility that increases redistribution: the possibility that non-elite leaders have been co-opted by elites. Voter uncertainty about whether non-elite leaders have been co-opted can lead moderate politicians to pursue even more redistributive policies than the median voter (a member of the non-elites) prefers. The greater their ability to credibly commit to a moderate policy agenda and to resist elite cooptation, therefore, the less redistributive are the policies that they follow.

In addition, parties able to make credible commitments are likely to have longer time horizons, leading them to take into account the long-run costs of excessive redistribution. Credible parties have longer horizons for at least two reasons. First, they can manage leader transitions and are less likely to dissolve in the face of leader departure. The management of leader transitions is

> 2 Pontusson et al. (2002) examine the distribution of wages in advanced industrial economies, finding that the wages of higher paid workers are significantly lower when governments are left-wing.  As with Scheve and Stasavage (2007), their analysis does not examine redistribution and the effects of government taxes and transfers on income equality.

4