It has long been evident the global "war on drugs" sparked by then US president Richard Nixon about half a century ago is one of the most tragic and abject failures in the history of public policy. Rather than reduce harm caused by substance misuse and addiction, it has cost countless lives by treating people with a medical problem as criminals. It has wasted a fortune in taxpayers' money. It has enriched criminal cartels. It has epitomised politicians' propensity to pander to fear, rather than to lead enlightened community change by championing evidence-based policy.

That is why The Age has for years been arguing the policy should be dumped in favour of a harm minimisation strategy based on decriminalisation, regulation and education. We continue to so advocate, and believe the resources being wasted on this misguided, indefensible "war" should be diverted from the criminal justice system to the health system, where there is a need for more treatment facilities and support to help those with drug issues recover and stay well.

Decriminalise it and regulate it. Prohibition has failed to minimise harm.

Today we repeat what we said five years ago: "The Age is not in any way seeking to condone or encourage the misuse of addictive substances, be they legal or illegal. On the contrary, we stress that addictive drugs are extremely dangerous, particularly for young people, whose brains are still developing and who are particularly vulnerable to drug-induced mental health problems. Drug addiction and misadventure cause tragedies. Far too many Australian families can attest to that. That is the point; we are arguing for a public debate about policies to minimise harm."

And so we welcome the courage and leadership of Greens leader Richard Di Natale, a former drugs and alcohol doctor, who in recent days convinced his party to abandon its blanket opposition to the legalisation of illicit drugs.