Reagan's "war on drugs" was a pathetic political maneuver to get votes from religionists who don't understand any of the issues and lack the cognitive skills necessary to grasp the consequences. As such, it fits in with most US political activity: immensely self-harming, stupid, but vote-rich. I rather suspect the only thing that will ultimately get rid of no-knock warrants will be a significant increase in police being killed while breaking into people's homes unannounced in the middle of the night. Perhaps this very real risk of death is why so few raids are actually conducted on drug dealers and instead are conducted on innocent (and perhaps therefore less well-armed and prepared) citizens.