I'm late to this thread, so there's upwards of 100 replies....
I think this is a necessary step, not because I approve of Marijuana, but because there are a lot of states that have legalized weed. The Federal law and the laws of the "several states" are in conflict, resulting in people being prosecuted and imprisoned despite State laws to the contrary.
It's a States Rights issue, subject to the 10th Amendment.
Then the FDA should be reduced to testing for purity, and no substance should be Federally controlled. Nowhere in the Constitution does it say the Federal Government has the power, except to provide for standards of weight and measure. Definitely not to regulate what people take by any means. (Goodbye Federal tobacco laws, too).
Of course, the Feds tie funding to what they want, and states roll over like gutshot hyenas...