In Guaranty Trust Co. v. United States (1937), the Supreme Court ruled on a dispute involving federal estate tax law and its application to life insurance policies. The case revolved around whether or not proceeds from life insurance policies, owned by the deceased but payable upon death to their estate, should be included in gross taxable estate under Section 302(g) of Revenue Act of 1926. The decedent had transferred ownership of his life insurance policies to Guaranty Trust Company with an agreement that the proceeds would be paid back into his estate after his death. The court held that these policy proceeds were indeed part of the gross taxable estate as they fell within "transfers intended to take effect at or after death" clause in Section 302(g). This decision was based on two key factors: first, despite transferring ownership rights, decedent retained control over beneficiaries; secondly, he continued paying premiums which indicated ongoing interest and control over said policies. This ruling clarified interpretation and application of federal tax laws related to estates and transfers occurring at or after death - reinforcing that such transfers are subject to taxation even if legal title has been passed onto another entity prior to owner's demise.

In the dissenting opinion for Guaranty Trust Co. v. United States, Justice McReynolds disagreed with the majority's interpretation of Section 5(b) of the Trading With The Enemy Act as it pertains to interest on bonds held by an alien enemy during World War I. He argued that this section does not authorize payment of such interest after a declaration of war and before settlement or vesting order is issued, especially when no demand has been made by any person entitled thereto within two years from date when right accrued. According to him, Congress did not intend to give away public money without clear statutory direction and there was no such directive in this case.