The USDA has been sued more than once. I myself was a plaintiff in one case led by the Center For Food Safety that was rejected by the courts, and again on appeal. They said the appeal decision was an unpublished opinion, meaning it couldn't be used as a legal precedent. They were not confident in their decision, but they were reluctant to go against the USDA. We might try again. I have learned that the courts do not always uphold the law. It is complicated.

I would argue that the USDA’s allowance of water-based (hydroponic) growing systems as certified organic is illegal and that this issue has not yet been addressed directly in any lawsuit I have seen. (It is worth mentioning that only in the US are these hydroponic systems considered organic; no other country in the world allows this.) Some of us believe a direct lawsuit is the best way forward - both to uphold the existing laws, and to raise public awareness that this is going on. Unfortunately, a lawsuit of the scale required here would require significant financial backing - not yet available to my knowledge.