For the first time in history the U.S. Senate has an active bill to legalize medical marijuana. Senators Cory Booker (D-NJ), Rand Paul (R-KY) and Kristen Gillibrand (D-NY) unveiled the bill at a press conference today.

Called "The Compassionate Access, Research Expansion, and Respect States – CARERS – Act," the bill would offer sweeping changes to federal marijuana laws and codify some existing practices.

In many ways it combines several bills that have already been introduced in the House of Representatives.

Should the bill pass both Houses and get signed by President Obama it may still be a mixed bag.

The introduction announces that the legislation will "extend the principle of federalism to state drug policy."

It would essentially give the federal government's blessing for states to enact their own medical marijuana laws without federal interference. But that has, obviously, already been happening. While some individuals have been targeted by federal prosecutors over marijuana, no state government or state employee has seen interference from federal authorities while implementing their laws. Indeed, the whole nature of American federalism is that states don't need permission from Congress to make such changes.

There is more concrete language.

One of the provisions in the new Senate bill allows military veterans under the care of the VA to access medical cannabis if they live in a state that has legalized it. The bill would allow VA physicians to recommend medical marijuana in these states, something that is currently prohibited. This is a big change. In 2011 the VA issued a policy guideline that stopped the ad hoc removal of vets from care if they tested positive for THC in a medical marijuana state, but still banned VA doctors from recommending the treatment.

Another aspect of the bill would allow more federal marijuana to be grown and distributed to academic institutions for medical research. Right now there is only one federal garden that supplies research cannabis under restrictions so severe that they make science difficult to conduct on the plant. The bill would allow three more providers.

The largest part of the bill deals with allowances made for banking. This could be the most welcomed provision by the medical and recreational cannabis industries already operating at the state level. Because all financial institutions are regulated by federal laws and agencies cultivators, dispensaries and retail stores have been forced to operate in a cash-only environment. A few companies have proposed banks and credit unions to serve the industry but have yet to gain federal approval.

The largest shift proposed in the Senate bill would, on paper, end absolute federal marijuana prohibition. It would move marijuana from Schedule I to Schedule II in the Controlled Substances Act (CSA). This would no longer allow some doctors and medical institutions (like the Pennsylvania Medical Society) hide behind federal policy in their opposition to changing state laws.

But unfortunately, changing the status in CSA may bring more problems than solutions.

The states have regulated cannabis without any federal oversight whatsoever. Agencies like the DEA, FDA, Office of National Drug Control Policy (ONDCP), National Institute on Drug Abuse (NIDA) and National Institute of Health (NIH) have been unable to impose extra rules or influence local regulations.

Move cannabis down in the schedule scheme, even one notch, and all the agencies listed above would suddenly have tremendous power over every aspect of the plant. The acronyms would come with their own armies of lawyers and lobbyists well honed in the realm of big medicine, pharma and government.

Moving marijuana to Schedule II may actually undo the state-level marijuana reform laws by putting the federal government back in the driver's seat. Alcohol and tobacco are not in the CSA. No Schedule II drugs (which include cocaine and Oxycontin) are legally sold for recreation.

Of course, there is another option, one that could (and should) still be considered. In order for federalism to truly prevail marijuana should be completely removed from the Controlled Substances Act.

De-scheduling is not a new theory. Raymond Shafer, a two-term Governor of Pennsylvania and a staunch Republican, first proposed it in 1972. Categorizing marijuana as Schedule I back in 1970 was supposed to be a temporary measure. Shafer was appointed by President Nixon to lead a group that was tasked with studying the categorization. He and his fellow commissioners could not find justification for the federal government enacting criminal prohibition or placing it in the CSA. Their full report, "Marihuana: A Signal of Misunderstanding," was insightful, prophetic and reads fresh 43 years later.

Sadly the bill won't help state expand overly limited local programs. Sen. Booker replied to a tweet today from a man whose father lives in New Jersey and doesn't qualify for the medical marijuana law's protection. Gov. Chris Christie has refused to expand the program and the U.S. Senate bill won't help in that regard.

Overall it is certainly profound that the Senate is considering the issue of medical marijuana. Senators Paul, Booker and Gillibrand should be applauded for their action. Yet the many potential pitfalls of the bill also demonstrate that federal legislators still need a lot of education about the problems with prohibition in order to find the solutions that will work best in the real world, not just on paper.

Chris Goldstein is associate editor of Freedom Leaf magazine and co-chair of PhillyNorml. Contact him at chris@freedomisgreen.com.