How do you know its not the other way round. That the government just follows the public opinion. At least, I don’t think its a fair comparison you make in the end. Let me ask: How many people do you think drank alcohol during the prohibition on a daily basis? How did that compare to the number og people who ate brussel sprouts on a regular basis?
It does, but it’s more insidious than that. When cannabis was first made illegal in the US in 1937, there were an estimated 35,000 smokers in the US, mostly migrant illiterate Mexican laborers. During the Congressional hearings held before the law was passed, the representative from the American Medical Association testified that he hadn’t heard of problems due to marijuana or that there was a need for its prohibition. But since it was a “narcotic” (and a deadly menace according to Harry Anslinger, head of the agency dealing with drugs then), it was outlawed. At that point, there was no firm “public opinion” on cannabis.
What’s important to remember that since drugs are illegal, the dominant source of information is the government. To conduct research on marijuana, you need govt. permission among others, so they control the studies that get done. The media also filters the information disseminated, and before the advent of the internet, that was a death knell, e.g. did you know that the federal govt. which denies any medical use of marijuana, has been supplying a limited number of patients with marijuana, or that a DEA law judge ruled in 1988 that keeping marijuana in Schedule I (no medical use) was “unreasonable, arbitrary and capricious”. It’s a vicous cycle: Illegal -> Government control -> Filtered information -> Public opinion -> Illegal -> …
/off-topic
Onto the OP
Define ‘work’. If what’s meant is total or near-complete eradication, then of course not.
If ‘containment’, then it’s a mixed answer. Use is contained significantly of the harder drugs, modestly of the softer drugs. Harm, not so much, since it may avert harm by reducing use, but it increases harms for those who do use (impurity, dealing with drug dealers, very high prices which can lead to crime…etc).