The Moores were taxed $14,729 on that investment under a provision in the GOP’s signature 2017 tax law called the “mandatory repatriation tax” (MRT), which imposed a one-time tax on U.S. individuals and companies who have a significant stake in foreign corporations controlled by Americans.

In a Supreme Court case revolving around one couple’s disputed tax bill, justices Tuesday wanted to explore the case’s potential broader implications, while opposing lawyers wanted them just to stick to the case at hand.

The case before the justices Tuesday could have sweeping implications for the U.S. tax system and derail proposals from some Democrats to create a wealth tax.