As time passes the children of the 'Anslinger Age' are fading away and leaving the political arena. We now have a President that understands the sense legalizing makes. Will he be the one to do it? Maybe yes maybe no. But if not him, someone in the pretty near future will. I just hope I am still alive to see it.
President Obama has made absolutely no indication whatsoever that his administration is interested in decriminalizing cannabis on a Federal level, and to the contrary, he's indicated that he won't. I wouldn't hold my breath for Obama to spend any bit of his dwindling political capital on liberalizing American MJ policy either. He's sure as hell not going to attempt it in an election year, and bluntly, the way things look for him right now, he'll be lucky to even have a second term in office to contemplate this.
I'd also make the argument to you that Presidents Clinton AND Bush (like Obama, both of whom have also effectively admitted to smoking marijuana) "should" also know that its not a particularly dangerous drug. The question isn't knowing or not knowing how safe/dangerous MJ is, its where the political capital is going to get spent. I don't think any US President is going to stick their neck out for MJ until and unless there is a strong public chorus demanding it.
Also, as a matter of practice, as Nixon was the only one who could "go to China", since his background (a Republican and diehard anti-communist) made that sort of move seem reasonable, instead of weakness, its probably going to be politically easier for a Republican president with a strong anti-crime background to liberalize Federal MJ restriction. A pot-smoking liberal like Obama would actually have a harder time pulling this off.
I'd also hasten to add that the Federal marijuana laws are just that. . .LAW. The President can choose not to enforce existing law, if he likes, or more precisely, to de-emphasize enforcement, but he can't by himself alter the law. If you want MJ truly legalized on a Federal level, that's going to take an act of Congress. . .the same Congress that banned it in the first place.
So if you think, for example, that voting for Ron Paul for President is going to create a Federal legalization of MJ, think again. At best Paul might not enforce Federal MJ law, and not harass the legal dispensaries, but that's probably about as far as he could go. Looking at Obama, he promised that he would have Guantanamo Bay closed immediately after taking office. . .three years later, he still didn't get it done, and I'd argue to you that closing a prison is a heck of a lot easier politically speaking than legalizing cannabis! The point is, its one thing to make pre-election promises, and quite another thing to actually pull them off while in office, even with good intent!
Any claims made by candidate Paul on this issue have to be taken with a gigantic grain of salt. He may sincerely want to reform Federal MJ law, but I don't think that the US Congress is anywhere near the point now where it would actually vote to do it. Remember, as a House member for 20+ years, Paul hasn't been able to liberalize Federal MJ law, nor even move the ball in that direction one inch. Why is he going to be able to pull it off as POTUS?
More to the point, even in California, one of the most pro-MJ States there is, that STATE couldn't pass prop 19 to legalize MJ, only two years ago. If the State of CA isn't able to legalize MJ now by simple popular vote, then there isn't a snowball's chance in hell that the entire US Congress (which includes representatives from socially conservative States like Alabama, Georgia, South Carolina, etc) is going to do it.
Bottom line, anyone who thinks that Federal reform of MJ law is just around the corner probably needs to put down the bong. While its true that the trends of State decriminalization, State-level medical MJ, and public opinion are all moving in the right direction, the movement is still slow, and I think we're looking at at LEAST 5-10 more years before Federal level decriminalization is plausible.