Party systems diverge in their levels of nationalisation. While in some countries parties obtain similar levels of electoral support in all districts, in others parties get very asymmetric electoral shares across districts. The distributive consequences of thiParty systems diverge in their levels of nationalisation. While in some countries parties obtain similar levels of electoral support in all districts, in others parties get very asymmetric electoral shares across districts. The distributive consequences of this have been seldom studied. The argument tested here is that when political parties have nationalised electorates they have stronger incentives to provide social policies that spread benefits all over the territory. This argument is tested in 22 OECD democracies for the period 1980-2006. The results show that, regardless of the electoral system in place, there is a positive relation between party system nationalisation and social spending.[+][-]