A SCOTUS case aiming to protect rich people from taxes could lead to chaos for the federal government’s finances.

The plaintiffs’ arguments in Moore v. United States have little basis in law — unless you think that a list of long-ago-discarded laissez-faire decisions from the early 20th century remain good law. And a decision favoring these plaintiffs could blow a huge hole in the federal budget. While no Warren-style wealth tax is on the books, the Moore plaintiffs do challenge an existing tax that is expected to raise $340 billion over the course of a decade.

But Republicans also hold six seats on the nation’s highest Court, so there is some risk that a majority of the justices will accept the plaintiffs’ dubious legal arguments. And if they do so, they could do considerable damage to the government’s ability to fund itself.