The U.S. Supreme Court case Commissioner of Internal Revenue v. McCoy, Executor of the Estate of McCoy (1987) revolved around a dispute over estate tax deductions related to marital property rights in Texas. The issue was whether or not the surviving spouse's interest in community property should be included as part of the gross estate for federal taxation purposes when calculating allowable marital deduction under section 2056(a) and (b)(1). The court ruled that only half - rather than all - of community property is includable in a deceased spouse’s gross estate, thus allowing an equivalent amount to qualify for the marital deduction from such an estate. This decision clarified how federal law interacts with state laws regarding community property and established precedent on this matter.

In the dissenting opinion for Commissioner of Internal Revenue v. McCoy, it was argued that the majority's decision to allow a deduction for estate tax purposes on an amount paid by the decedent prior to death as part of a property settlement in divorce proceedings contradicted previous rulings and interpretations of relevant statutes. The dissenting justices believed that such payments should not be considered debts deductible from an estate’s gross value because they were voluntary transfers made while alive rather than obligations at death. They also pointed out inconsistencies in how similar cases had been handled previously, suggesting this could lead to confusion and unpredictability in future decisions. Furthermore, they expressed concern about potential misuse or manipulation of deductions if allowed under these circumstances.