The Supreme Court is poised to hear arguments Tuesday in a closely watched case that some warn could have sweeping implications for the U.S. tax system and derail proposals from some Democrats to create a wealth tax.

The dispute before the justices, known as Moore v. United States, dates back to 2006. That year, Charles and Kathleen Moore made an investment to help start the India-based company, KisanKraft Machine Tools, which provides farmers in India with tools and equipment. The couple invested $40,000 in exchange for 13% of the company’s shares.

KisanKraft’s revenues have grown each year since it was founded, and the company has reinvested its earnings to expand the business instead of distributing dividends to shareholders.

The Moores did not receive any distributions, dividends or other payments from KisanKraft, according to filings with the Supreme Court. But in 2018, the couple learned they had to pay taxes on their share of KisanKraft’s reinvested lifetime earnings under the “mandatory repatriation tax,” which was enacted through the Tax Cuts and Jobs Act, signed into law by President Donald Trump the year before. The tax was projected to generate roughly $340 billion in revenue over 10 years.