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It’s been 40 years since President Nixon’s “War on Drugs.” Is it possible that peace talks are now at hand? On Thursday, President Obama said the question of drug legalization and regulation is an “entirely legitimate topic for debate” — the first sitting president to do so since cocaine, heroin and marijuana were made illegal in the U.S.

In a question-and-answer session on YouTube, in which the top 10 questions submitted to the President focused on drug policy, Obama responded thoughtfully to that query from a representative of Law Enforcement Against Prohibition, a group of former law enforcement professionals whose experience on the streets has led them to conclude that drug prohibition actually drives crime and does not solve drug problems.

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While Obama made clear yesterday that he opposes legalization, his larger response marked a shift from his previous answers to such questions, which have been dismissive and patronizing. In 2009, the top questions presented by viewers on YouTube were also about drugs, but at that time, he shrugged off the issue. In response to a question about marijuana legalization, he said simply that it wouldn’t be a good way to grow the economy. (More on TIME.com: 7 Tips for California on How to Make Legalization Smart)

Yesterday, he discussed more fully his own position about the nation’s drug problem — that drugs should be seen as more of a public health issue, and that efforts should be made to reduce waiting times for drug-treatment programs and to help keep nonviolent first offenders out of prison. “On drugs, I think that a lot of times, we have been so focused on arrests, incarceration, interdiction that we don’t spend as much time thinking about, How do we shrink demand?” the President said.

No other President has ever dared to suggest that a realistic debate on drug policy must include key questions about the effectiveness of absolute prohibition. With former Mexican President Vicente Fox calling for drug legalization — and given that Prop 19, California’s marijuana legalization measure, garnered 46.5% of the vote — it may be time to have a calm, adult conversation about what the evidence really shows about current drug policy, and what the best ways to reduce drug-related harm may be.

More on TIME.com:

With 12,000 Dead in 2010 from Drug Violence, Mexican Ex-President Calls for Legalization