What makes a President retreat from sanity?

Just some random thinking…
It seems likely that Obama, when President, will end the raids on medical marijuana, particularly in states that have approved it.

“I would not have the Justice Department prosecuting and raiding medical marijuana users. It’s not a good use of our resources.”

That’s pretty clear. And yet, if we go back 8 years, we find another Presidential candidate named George W. Bush talking, in his unique style, about medical marijuana…

“I believe each state can choose that decision as they so choose.”

That was pretty clear, too. I don’t doubt that he believed it.
So what happened? Did he suddenly lose all interest in federalism when he was inaugurated? Was it as simple as that? It seems unlikely. That would, at most, have resulted in indifference.
Or did someone sit him down after he was elected and explain to him that there were important political reasons to stomp down hard and consistently on medical marijuana? Because, after all, the last eight years have seen a powerful, coordinated, federal attack against the concept of medical marijuana. If so, who sat him down, and what was that explanation? I’d really like to know.
Will someone sit down President-elect Obama and have the same conversation? Will his position suddenly and inexplicably reverse? I’m not expecting it, but given my uncertainty about what actually happens in the rarified circles of political decision-making, who is to know?
Obama’s position is, at least, seemingly grounded more in a sense of rightness about the issue (as opposed to just an abstract general feeling about federalism) so that may be a difference.
There is, I believe, also a stark difference in the public discourse about drug policy and the drug war in general between 2000 and 2008. We have come light years in terms of public views (76% now think the drug war is a failure) and the potential for political/press cover for drug policy reform views.
After all, today we see in papers all over the country, OpEds like this one from Bill Steigerwald, who has suggestions for Obama.

On the homefront, there’s another hugely important change you could quickly bring America: Call off the federal government’s bipartisan war on drugs.
You could get on TV some Tuesday night and tell your fellow Americans the truth most of them have known for decades: The dirty drug war waged by government on its own people has failed by every measure.
Then reassert your forgotten call for America to start treating all drug use as a health issue instead of a criminal justice issue. Then give your presidential blessing to the decision by Massachusetts voters last week to approve the country’s first marijuana decriminalization initiative.
Then make marijuana as legal as beer. Then pardon all nonviolent drug offenders. Then decommission the DEA. Then, using your best oratorical skills, declare a great victory in America’s never-ending war against too much government and too little personal freedom.

OK, maybe they’re not all as strong as Steigerwald, but still… it is a different world.
I recently got the entire The West Wing
series and have been watching it. In Season 2, Episode 15 (“Ellie”), the Surgeon General makes some innocuous true statements about marijuana (“Marijuana poses no greater health risk than nicotine or alcohol”, etc.) that sets off a political firestorm almost leading to her firing (possibly a comment on the Joycelyn Elders tenure). As the President’s staff tries to figure out what to do to limit the damage, we have this exchange:

President Bartlet: Who’s coming to her defense?

Josh: The Cannabis Society, the Cannabis Coalition, E Cannabis Unum, the American Hemp League, and Friends of Mary Jane.

[…]

President Bartlet: I’ve got to hand it to you guys… you’ve managed to win me the support of the Christian Right [separate issue] and the Cheech and Chong Fan Club in a the same day.

OK, it’s clearly written for entertainment value, but the stereotypes used point out how far we’ve come in just the last decade. That episode would be much less believable today.
So yes, clearly we’ve come a long way, and the political cover that brings gives me some guarded optimism about what might happen in a new White House.
And yet, I still go back to 2000 and newly elected George W. Bush’s reversal on medical marijuana, and I ask: Who set him down and what did they say to him?