On November 18, 2025, United States v. Sirois finally came to an end when Lucas Sirois and his father, Robert Sirois, were found guilty in the District of Maine on multiple charges related to a conspiracy to cultivate and distribute thousands of kilograms of marijuana on the black market.

Background of the Sirois Case

We first covered Sirois in a November 2024 post and then revisited the case in a March 2025 post. Suffice it to say, there is a lot to learn from this case – particularly, what not to do as medical marijuana operators.

As a refresher, the Sirois case began back in November 2021 when more than a dozen individuals were charged in connection with an alleged conspiracy to sell marijuana illegally. The individuals included Lucas and Robert Sirois, as well as an assistant district attorney and two former deputies. The leader of the conspiracy was allegedly Lucas Sirois, who was licensed to grow medical marijuana in Maine. What appeared on paper to be a network of caregiver operations and licensed marijuana businesses was in reality something much larger and much less legal.

After the defendants were indicted, the defense attempted to halt the prosecution altogether by relying on the Rohrabacher-Farr Amendment, which prevents the Department of Justice from spending funds to prosecute individuals acting in strict compliance with state medical marijuana laws. Ultimately, the First Circuit affirmed the district court’s holding that the Sirois defendants were not immune from prosecution because they had not shown that their activities “substantially complied” with Maine’s medical marijuana laws.

Then in February 2025, the Sirois defendants filed a petition for writ of certiorari to the U.S. Supreme Court asking the high court to shift the burden of proof away from the defendant to the DOJ when the defendant relies on the Rohrabacher-Farr Amendment to avoid federal prosecution. In March 2025, the Supreme Court rejected the petition for writ of certiorari.

The Trial and Arguments

After those proceedings, on November 12, 2025, the trial against Lucas and Robert Sirois finally began (as all of the other individuals charged had previously pleaded guilty). At trial, the defense argued that the U.S. Drug Enforcement Administration did not seize marijuana when it raided the defendants’ buildings, but rather they seized hemp. The defense also argued that the defendants believed they were following Maine law and were growing marijuana for legitimate medical marijuana operations. Alternatively, the government argued that the defendants built a network of grow locations merely disguised as medical marijuana facilities and then sold marijuana on the black market and hid their profits through real estate deals and shell companies. In the end, the jury sided with the government, finding Lucas Sirois guilty of participating in the conspiracy to cultivate and distribute marijuana, as well as tax and bank fraud. Robert Sirois was also found guilty of participating in the conspiracy.

Sirois first piqued our interest because of the case’s potential implications related to the Rohrabacher-Farr Amendment. But, in the last chapter of the Sirois case, we learn that itcan also inform us about how medical marijuana compliance may (or may not) be included in trial evidence.

Legal Motions and Evidence Issues

Prior to the start of the trial, the government filed a motion in limine, requesting that the defendants be precluded from offering evidence or eliciting testimony about “Maine laws regarding medical marijuana, the ‘medical necessity’ of marijuana, the possible legalization of marijuana, the defendants’ status as medical marijuana caregivers, sales to legitimate medical marijuana dispensaries, other marijuana wholesalers or patients, and the defendants’ beliefs about Maine’s marijuana laws.” The government argued that this evidence was irrelevant, posed a substantial risk of confusing the issues and misleading the jury, and invited jury nullification. Additionally, the government requested that the jury be instructed as to the irrelevance of the defendants’ compliance or noncompliance with Maine law at the beginning of the trial.

In response to the government’s motion, Robert Sirois argued that he was “entitled to argue that he did not possess the requisite mens rea to commit the crimes he ha[d] been charged with.” He stated that the government’s attempt to strike all evidence related to Maine’s medical marijuana laws was an “attempt to create a fantasy world where [his] actions cannot be seen in the reality in which they occur[red].”

Similarly, in his response to the government’s motion, Lucas Sirois argued that complete exclusion of Maine’s medical marijuana laws would “not only distort the evidentiary picture under [Federal Rules of Evidence] 401-403, but would also trench upon the defendant’s Six Amendment right to present a complete defense and to confront the Government’s narrative on intent and purpose.” Lucas Sirois requested that the court deny the government’s motion in full or, alternatively, narrow the limits on the presentation of any medical marijuana compliance evidence. Specifically, he requested (1) preclusion of only the argument that state law is a complete legal defense to federal controlled substances charges; (2) allowing evidence and cross-examination about Maine’s regulatory framework, caregiver status, sales channels, communications with regulators, and defendants’ beliefs/efforts for the limited purposes of intent, knowledge, purpose, materiality, context, and impeachment; and (3) that any instruction given be neutral.

Ultimately, the court granted the motion in limine in part and denied it in part. In coming to its conclusion, the court discussed Federal Rule of Evidence 403 — that is that “relevant evidence may be excluded ‘if its probative value is substantially outweighed by a danger of one or more of the following: unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, or needlessly presenting cumulative evidence.’” The court went on to explain how evidence that may invite jury nullification should be excluded from trial.

In its order, the court stated that it agreed with the government “that the regulatory and legal landscape that governed the distribution and use of medical marijuana in Maine between 2016 and 2020 has only marginal relevance to the charged offenses, if any.” The court continued: “Evidence of compliance with state marijuana laws does not negate the mens rea required under the Controlled Substances Act for the offenses with which Defendants have been charged.” And the court made the point that it would “not entertain a trial within a trial about the Defendants’ compliance with Maine medical marijuana regulations, when that issue has already been litigated before two courts, who both decided that Defendants did not demonstrate compliance sufficient to enjoin the prosecution of this case.”

However, in the end, the court ruled that “the discussion of Maine’s regulations may be unavoidable,” therefore, if the parties decided to pursue an examination on the subject of such regulations, a side bar to discuss objections would be held. Additionally, the court concluded that a preliminary instruction to the jury would be appropriate to inform them that compliance with Maine’s marijuana laws and regulations is not a defense to the federal crimes of distributing marijuana, possessing marijuana with the intent to distribute, or conspiring to do so.

Implications for Medical Marijuana Operators

The court’s order on the government’s motion in limine parallels the rulings made earlier in the Sirois case related to the Rohrabacher-Farr Amendment because both seek to separate state medical-marijuana laws from the federal prosecution framework, preventing defendants from using state-law compliance as a defense or from confusing jurors about the supremacy of federal drug law. Together, the government’s motion in limine filed in the Sirois trialand Sirois’ previous rulings related to the Rohrabacher-Farr Amendment send a clear message: Medical marijuana operators cannot conclusively rely on state compliance or a state license to shield themselves from federal prosecution. The motion in limine shows that courts can block defendants from arguing state legality to jurors, and the amendment will protect operators only if they are strictly compliant with every aspect of state medical marijuana law. As a result, medical marijuana businesses must operate with extreme caution and in strict compliance with state law.