Charles and Kathleen Moore are about to have their day in the Supreme Court over a $15,000 tax bill they contend is unconstitutional.

The couple from Redmond, Washington, claim they had to pay the money because of their investment in an Indian company from which, as Charles Moore, 62, said in a sworn statement, they “have never received a distribution, dividend, or other payment.”

But significant parts of the story they have told to reach this point seem at odds with public records. The Moores are the public face of a high court case backed by business and conservative political interests that could call into question other parts of the U.S. tax code and rule out a much-discussed but never-enacted tax on wealth. The case is set for arguments on Dec. 5.

The Moores are the latest example of plaintiffs whose lawsuits seem to simply be exercising their legal rights, but whose cases are backed by others with enormous amounts of money or a consequential social issue at stake. The Moores sought help from the anti-regulatory Competitive Enterprise Institute.

Underscoring the case’s importance at a recent Heritage Foundation event, lawyer Paul Clement said, “The constitutionality of a wealth tax may well be decided in the context of this case.”

Details of the Moores’ involvement with the company, initially called KisanKraft Machine Tools Private Limited, were first reported by Tax Notes, which caters to tax professionals. The public documents are filings with the Indian government.