In this case the Defendant engaged in a "scheme" charging contractors to place fill in what met the regulatory definition of wetlands but may or may not have been completely dry at the time.  All three judges on a panel of the 9th Circuit Court of Appeals set aside his Federal Clean Water Act criminal conviction for that scheme because the Jury was not instructed that the Defendant needed to knowingly discharge the fill, a pollutant under the Act, into "water" to be convicted of a violation of the Clean Water Act.

Where the Dissenting Judge parts company with her colleagues is with respect to whether one also needs know that the "water" is a "Water of the United States".  The majority says no, while a discharge to a "Water of the United States" is required for the law to apply at all, you don't need to know whether or not a water is a "Water of the United States" to be criminally convicted of violating that law.  If the United States retries this Defendant, this might not be the last word on this.

The panel also rejected the Defendant's assertion that the "Waters of the United States" standard against which his 2014 conduct should be judged is the 2020 EPA regulation supplying yet another definition for "Waters of the United States."  That certainly makes sense as far as it goes.  But what about the fact that the prior regulation was only the law in half of the States of the Union owing to several challenges of its validity?  What about the fact that the same is true of the 2020 regulation? Can one really be guilty of a violation of federal law in half of the states?   According to this decision, the answer to that question is apparently yes.