For months, many have worried that the Trump administration would initiate a crackdown on marijuana in states where it's legal. So far, Attorney General Jeff Sessions has been kept on a leash and prevented from doing so. But according to Sessions' number two, that may change.

Deputy Attorney General Rod Rosenstein appeared at the conservative Heritage Foundation yesterday and implied that the Department of Justice is investigating ways to begin their marijuana crackdown.

"We are reviewing that policy. We haven't changed it, but we are reviewing it. We're looking at the states that have legalized or decriminalized marijuana, trying to evaluate what the impact is," he said. "And I think there is some pretty significant evidence that marijuana turns out to be more harmful than a lot of people anticipated, and it's more difficult to regulate than I think was contemplated ideally by some of those states."

The policy Rosenstein refers to is the "Cole Memo," which was a set of criteria the DOJ sent out in 2013 to states with legalized medical or recreational marijuana. The memo said as long as the states' met certain criteria, such as limited marijuana use by teens and impaired driving incidents, the DOJ would not intervene.

Rosenstein says the memo has been misinterpreted and, even with the policy in place, there's wiggle room for the DOJ to still intervene.

"That's been perceived in some places almost as if it creates a safe harbor, but it doesn't. And it's clear that it doesn't," he said. "That is, even if, under the terms of the memo you're not likely to be prosecuted, it doesn't mean that what you're doing is legal or that it's approved by the federal government or that you protected from prosecution in the future."

Of course, even if Rosenstein's interpretation of the Cole Memo justifies a marijuana crackdown, other laws are in place that would prevent him from doing so. The Rohrabacher-Blumenauer amendment, a law passed by Congress that prevents the Department of Justice from using its resources to intervene in the medical marijuana industry, was extended until December last week. And considering the amendment has bipartisan approval, it's likely it will be extended again before the next deadline.

But if what Rosenstein and Sessions tell the press is accurate, as soon as those protections go away, they will target marijuana.