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A New I Do: Towards a Marriage-Neutral Income Tax

60 Pages Posted: 11 Apr 2006  

Shari Motro

University of Richmond - School of Law


The federal income tax system treats married couples as if each spouse earned approximately one-half of the couple's combined income through a mechanism called income splitting. For many one-earner and unequal-earner couples, income splitting produces a significant advantage, a marriage bonus, by shifting income from higher to lower rate brackets. Marriage-based income splitting relies on a presumption that marriage is a good indicator of economic unity between two taxpayers. It is not. Marriage does not require spousal sharing and many unmarried couples share everything they earn. As a result, the current system extends the benefit of income splitting to some taxpayers who do not deserve it while withholding it from others who do. Because marriage is a poor proxy for economic unity, this Article proposes a new eligibility criterion for income-splitting: only couples legally committed to sharing their income, regardless of marital status, would be permitted to file jointly.

Keywords: tax, marriage, gay, same-sex, community property, equality, contract, partnership, income splitting, joint returns, Earl v. Lucas, Poe v. Seaborn

JEL Classification: H2, H21, H24, J12, J13, J16, J21, J24, J24, K34

Suggested Citation

Motro, Shari, A New I Do: Towards a Marriage-Neutral Income Tax. Iowa Law Review, Vol. 91, p. 1509, 2006. Available at SSRN:

Shari Motro (Contact Author)

University of Richmond - School of Law ( email )

28 Westhampton Way
Richmond, VA 23173
United States

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