In the United States v. Byrum case of 1971, the Supreme Court ruled in favor of Byrum, who was being challenged by the Internal Revenue Service (IRS). The IRS argued that Byrum's retained control over shares transferred to a trust should be included in his gross estate for federal tax purposes after he passed away. However, Mr. Byrum had legally transferred these shares into an irrevocable trust years before his death and only retained voting rights on those shares as any ordinary shareholder would do so without having direct economic benefit from them. The court held that retaining such powers did not constitute possession or enjoyment of property under Section 2036(a) of the Internal Revenue Code because it is subject to fiduciary constraints and state law limitations against self-dealing which makes it impossible for him to use this power for personal financial benefits. Therefore, they concluded that these assets were not part of Mr.Byrum's taxable estate.

In the dissenting opinion for United States v. Byrum, Justice Blackmun argued that the majority's interpretation of Section 2036(a)(2) was too narrow and failed to consider its legislative history. He contended that Congress intended this section to include situations where a person retains power over property transferred into trust, even if such control is shared with others or subject to fiduciary duties. In his view, Mr. Byrum retained significant control over the stocks he placed in trust by reserving the right to vote them and decide when dividends would be paid out - powers which could affect their value significantly. Therefore, these assets should have been included in his gross estate for tax purposes upon his death.