"We need to educate Americans about the real harms of marijuana if we want to sustain the gains we've made over the past three years"

In this quote, John Walters is emphasizing the importance of informing Americans about the unfavorable results of marijuana. He believes that this is essential in order to keep the development that has actually been made in the past three years. By "genuine harms," he is likely describing the potential physical, psychological, and social consequences of using marijuana. Walters is recommending that without correct education, individuals might not totally comprehend the dangers related to marijuana use and may continue to engage in it, which could ultimately undermine the development that has actually been made in dealing with the issue. Therefore, he is promoting for a thorough and helpful approach to informing the public about the threats of marijuana.