You once said that when you were young, you "inhaled frequently. That," you said, "was the point."
Yet nowadays your chief of staff and your drug policy czar say that legalization is "not in [your] vocabulary." You oppose the legalization effort in California, and presumably the ones in Washington State, Oregon, and the city of Detroit as well. You want to continue to send more weapons to Mexico to escalate the drug war that is already killing thousands of people every year (7 murders a day in Juarez alone), and destroy the lives and careers of thousands of Americans for enjoying the same simple pleasure that you have "frequently" partaken of.
Mr. President, do you really think the current policy has merit? I don't think so. When you weren't running for president, you said we needed to reform our laws. As a marijuana smoker yourself, you know first-hand how innocuous the stuff is. No, I don't believe that you think marijuana should be treated as a dangerous substance, or its use as a federal crime. Rather, I think you lack the courage to stand up and say what you know to be the truth: cannabis is, as the DEA has said, the safest therapeutically active substance known to man; and the "war on drugs" - which is really a war on drug users, mostly marijuana users - is itself far more harmful than that which it purports to try to prevent.
I could be wrong, of course. But if you truly think marijuana use should be criminalized, and that its users should face the harsh criminal penalties that they do, then I submit that you should lead by example. You should waive your protection under the statute of limitations and turn yourself in for your unprosecuted drug crimes. You should plead guilty in a court of law to possession and, as may be appropriate, cultivation, distribution, conspiracy, and whatever other laws your own marijuana use violated. You should then face whatever penalties are involved - including civil asset forfeiture, mandatory minimum prison sentences, loss of your right to vote or hold office, and any other punishment that the system you support metes out to those who, unlike yourself, are not so lucky as to avoid arrest and prosecution.
Legalization and regulation will someday allow responsible adults to use cannabis in preference to more dangerous substances that are (and should remain) legal. It will offer economic benefits. It will reduce prison crowding, and free up the police to fight real crime. It will enable regulation of cannabis and eliminate the black market that has turned an estimated one million schoolchildren into drug dealers.
[Edited to correct the list of places that have legalization efforts in progress.]