A lot of police are against the war on drugs. They get to see the damage it's caused first hand.
The real good ones are against it, they are not interested in bloated police budgets and bloated prison system to build more prisons and to employ more and more cops. They believe the war is unbeatable and things seem to be that way, you don't need to be rocket scientist to tell things are not going well at all on that department.
You can blame Mexico and Colombia whatever you want. But US pop culture romanticizes drugs like no other so, why not legalize them?