The Crackdown on Medical Marijuana: Prohibition Revisited?

Sixteen states and the District of Columbia have legalized medical marijuana, but it's still an illegal, "Schedule 1" drug under federal law. Now the Obama Administration is cracking down, insisting that medical marijuana is a front for recreational use, and generating huge, illicit profits. The poster child is California, which started the movement in 1996 and where medical marijuana reportedly is a multi-billion-dollar business. Is the federal government blind to “compassionate use" by needy patients? Is medical marijuana a scam? What are the parallels to the era of Prohibition?