And in my view the current Attorney General is carrying out the same old ideas and policy effects, which is why he's so neurotically anti-weed, conflating it at every turn with opioid addiction.
Sessions has made statements in line with that description, but as yet they don't seem to have manifested in substantive DoJ action.
Of course, part of it may be that while posturing is supported by the administration, a major new FBI law enforcement initiative would be incompatible with the Administration’s propaganda war on the FBI, making it hard for it to get the green light.
Rohrabacher-Farr only applies on its face to state medical cannabis laws, and in any case Trump's signing statement on the spending bill containing the first renewal during his administration implied that the administration views the provision as unconstitutional. So, there's certainly action that the DoJ could take consistent with the administration rhetoric, from a couple different angles. It would hardly be the only example of this administration aggressively probing the limits of its power until and unless explicitly constrained by the courts.
Trump is crazy right? Sessions is a fascist right? Why haven't they unleashed the US Government very aggressively to raid and abuse the states? Who can stop them from doing that? Nobody. They aren't doing it. As far as comparing versus past AG behavior, Sessions is acting like a libertarian (again, by contrast to how things used to be during peak drug war). When California legalized pot for medicinal use, people all up and down the liberal Clinton Administration tried to argue / fight against it. I don't see the Trump Admin doing much of anything toward California (and the rest, DC, Washington, Colorado, et al) on this legalization front.
https://www.politico.com/magazine/story/2017/07/20/jeff-sess...
Sessions once said that he considered the Klan to be OK guys until he found out they smoked weed. He can't go fully anti-weed until Rohrabacher-Farr is undone by Congress, and he has been vigorously asking Congress to do so. Why would he campaign against it, unless he intended to immediately instruct DoJ and DEA to act against states who have made it legal? He has made it absolutely clear that he doesn't just intend to go after recreational weed, but medical as well. Libertarian? I do not want whatever you're smoking.
He hasn't done anything, even things that were in his power to do.