On December 5, the Supreme Court heard oral arguments on Moore v. United States, which is potentially the next landmark tax case on the meaning of income under the Sixteenth Amendment. We put together the highlights here, and you can get the official transcript here.

The Moores are challenging the one-time transition tax enacted under the Tax Cuts and Jobs Act (“TCJA”) on earnings that have accumulated overseas, arguing that the Sixteenth Amendment does not give Congress the power to tax “unrealized” income. Tax experts (and many others) caution that if the transition tax is declared unconstitutional, then numerous provisions of the tax law could be called into question for (seemingly) imposing taxes on unrealized income. Until then, we continue to eagerly await the Supreme Court’s decision.

While you wait for the page to refresh on Docket No. 22-800, here are the links to the Moores’ briefs arguing that the tax is unconstitutional:

For the arguments to uphold the tax, see below:

• Petition for Writ of Certiorari filed by the Moores
• Reply Brief to the opposition filed by the Moores
• Merits Brief filed by the Moores
• Reply Brief filed November 15

For the arguments to uphold the tax, see below:

• Decision from the Ninth Circuit affirming the district court’s dismissal of the Moores’ challenge
• Brief for the United States filed in opposition to the petition
• Brief for the United States filed October 13
• Amicus Brief of Professors of Law and Linguistics on the definition of “income,” cited by the Solicitor General during oral argument