Although the court will hear cases this fall involving the rights to bear arms, the authority of federal agencies, and whether the phrase "Trump too small" can be trademarked, Moore v. United States could have the most impact on Biden. That argument concerns whether Biden may impose a wealth tax, something he has frequently advocated.

"Reward work, not just wealth. Pass my proposal for a billionaire minimum tax," Biden said during the State of the Union address earlier this year. "Because no billionaire should pay a lower tax rate than a school teacher or a firefighter."