A study on the effects of both political orientation of governments' parties and a country's trade unionization on its income inequality.
It finds that, generally, strong unionization is strongly related to decreasing income inequality, most likely through a redistribution of political power through collective mobilization in national contexts of stronger unions.
It also suggests that in contexts of weaker unionization, post-redistribution income inequality is higher, thus also fostering unequal redistributive policies.
Lastly, it finds positive relations between right-wing orientation of a country's government and its income inequality, with more mixed results for centrist governments pointing to potential fragmentations in their redistributive policy approaches.
The study is mostly limited in not being able to account for individual drivers (or barriers) and can thus not disaggregate for the effects for example arbitration or collective bargaining.