The Politics of Couples' Taxation: The Introduction of Income Splitting in Germany, the US and France

Tax policies reflect societal structures and hence also entail gender biases. Joint taxation, for instance, which taxes married couples as a unified entity, creates a significant disincentive for secondary earners (predominantly women) to work. In contrast, individual taxation—where spouses’ incomes are taxed separately—does not interfere with women’s work choices and therefore supports their economic independence. Previous research on the politics of married couples’ taxation has mainly examined why joint taxation—often established at the same time as national tax systems—was abolished in many Western democracies. However, Germany, the US, and France first used mostly individualized tax systems before shifting to joint taxation with income splitting in the 1940s and 1950s. This paper therefore examines why major economies such as Germany, the US, and France reintroduced joint taxation, a gender-discriminatory tax policy which they still adhere to today. The historical comparative case studies show that joint taxation with income splitting was used to reinforce the traditional breadwinner model and strengthen marriage, in part to promote population growth after the Second World War. The analysis also situates this policy within the context of a postwar political culture favoring highly progressive postwar tax systems. Individual taxation was considered unsuitable, as it would have reduced taxes for high-income couples and made tax evasion easier. Governments instead implemented joint taxation with income splitting, providing a tax advantage for the majority of married couples. The taxation of married couples was thus closely tied to issues of gender, marriage, and class. The introduction of joint taxation was therefore intended not only to reinforce the traditional gender order but also to preserve the progressivity of the tax system. Overall, this research provides a valuable addition to the literature on gendered politics by exploring the often-neglected area of gendered tax reforms from a historical perspective.