It may go without saying, but then ask these guys.
In 2012, the three of them were growing pot east of Sacramento, California when local police served a search warrant for their property. They readily told police they were using the property to grow pot under state law, but it turned out their actual grow was on federal land.
The thing is, it’s not clear they knew it was federal land; in fact, it seems they didn’t know.
But that didn’t matter because the government didn’t have to prove they did. So they get charged federally for drug trafficking, and then they’re probably scared to death. One of them pleaded guilty before trial while the other two took their case to a jury, which hung. Back to the drawing board for them.
They moved to dismiss the case because it was 2016 by then, and in 2015, Congress had banned the Justice Department from using any funding to interfere with state laws on medical marijuana.
In fact, the federal appeals court for California had already ruled that people could rely on that ban to stop the government from prosecuting them for conduct that complied with state law.
But that ruling didn’t apply to them because they grew their pot on federal land. The Congressional ban speaks to a need to respect state law, but it says nothing about the enforcement of federal law on federal land. It also says nothing about recreational pot, but that’s another story.
Their case is still pending.