I believe the United States has set a precedent that has divided some states from the federal government. It truly makes no sense to have something illegal at the federal level, yet perfectly legal to the State and local governments. This gap is worst in states where marijuana has been fully legalized. I do believe the federal government should abstain to fight medical marijuana when the local governments have declared, by popular vote, that it is legal. It makes no sense for tax payers at all.
Be it Alcohol, prescription, or jesus we are all getting high on something. So why create the huge expense of keeping Weed illegal ? It is no more a "gateway drug" than Alcohol or Cigarettes and doesn't have the health risks. Not to mention the taxes it will bring in.