We regulated it as a means to police certain communities.

Hell, Billie holiday suffered from addiction but that bastard Harry Anslinger ordered doctors to not treat her and not provide her with methadone. She died with police stationed at her hospital room door. The FBI also harassed her over songs about lynching.

Nixon is literally on tape saying to go after weed and heroin more harshly as an excuse to arrest more anti-war protesters and civil rights protestors.

I'd argue "cracking down" has done little for controlling drug abuse and has primarily been a method for selective policing. Particularly in the states.