In the case of McGann v. United States, 1959, the Supreme Court ruled on a matter related to tax law and insurance policies. The petitioner, John J. McGann had purchased an endowment life insurance policy in 1928 with a face value of $50,000 which matured in 1953 when he was still alive. He argued that only the excess over his investment (the premiums paid) should be taxable income rather than the full amount received upon maturity of the policy as determined by Internal Revenue Service (IRS). However, IRS contended that since he had deducted all his premium payments from his gross income for federal income tax purposes during those years under then-existing laws allowing such deductions; hence now entire proceeds must be treated as taxable income. The Supreme Court upheld this view and rejected McGann's argument stating that it would result in double deduction benefit to him - once at time of paying premiums and again at receipt of maturity proceeds - which is not permissible under tax laws. Therefore, it held that entire amount received on maturity was indeed taxable.

In the dissenting opinion for McGann v. United States, it was argued that the majority's decision failed to properly interpret and apply the relevant statute. The dissent disagreed with the majority's view that a taxpayer who had not yet paid his tax could be penalized under a provision meant to punish those who fraudulently claim refunds or credits. They contended that this interpretation expanded the scope of criminal liability beyond what Congress intended when they enacted this law. Furthermore, they pointed out inconsistencies in how similar cases were handled by different courts due to varying interpretations of this statute, which further underscored their belief that clarity and consistency in its application were needed from Supreme Court’s ruling on such matter.