The Supreme Court, in the case of Moore v. United States, ruled in June 2024 that a mandatory repatriation tax on undistributed foreign corporate earnings was constitutional, affirming that income realized by a corporation could be attributed to its shareholders for tax purposes. However, the ruling did not definitively settle the broader question of whether Congress can tax unrealized capital gains in all contexts, as the specific tax in Moore involved income realized by the corporation itself. Proposals to tax unrealized capital gains for wealthy individuals, such as those from the Biden-Harris administration, are still under consideration and face significant legal and implementation challenges, including potential constitutional questions regarding the 16th Amendment and the definition of "income." Therefore, the prediction that taxing unrealized capital gains will be an impossible tax to implement due to fundamental legal challenges remains an open question, with ongoing debate and no definitive legislative or judicial resolution confirming its impossibility as of early 2026.