It's a fight he cannot possibly win. The momentum is on the side of the voices to legalize even more. What he should do is start preparing the nation and the people for a county failing under the weight of addictions.
Legalize it. But you have to grow your own. Shut down border with Mexico and get drug lords out of business. Make sure every state has roadside test for driving under influence. Allow employers to test during workday.
Can't do testing during the workday. Pot stays in the system up to 30 days. You smoke in the evening, it's still in your system, although no longer affecting you, the next day at work.
That's another reason pee tests are such colossal bullshit that need to be abolished yesterday. Completely aside from being a blatant disregard of the Fourth Amendment, it's bullshit reasoning. If employers were truly interested in "workplace safety", all they'd need to do would be to administer a simple reflex-timing test. It would cost next to nothing, it would produce results in literally seconds, and it would flag any worker who's under par whether it's from cannabis..... fatigue/lack of sleep...... alcohol or alcohol hangover..... distraction from their personal life......... oncoming illness even one the worker may not be aware of .... or any other reason.
IF they were actually looking for worker safety. But of course that's not what they're after --- they're after ABC --- Authoritarian Behavior Control. They see an opportunity to play the role of Big Brother and they want a piece of it.
That's why every citizen should stand up for his/her Fourth Amendment right and flatly refuse to give 'em the inch they want while they drool over the mile they'll get. People need to quit rolling over for this intrusive shit.