The Commerce Clause reads: "The Congress shall have Power... To regulate Commerce with foreign Nations, and among the several States, and with the Indian tribes" (Ivers, 2013). It's important to note that in James Madison's (Father of the Constitution) notes on the Constitutional Convention, "in no instance is the term "commerce" clearly used to refer to "any gainful activity" or anything broader than trade" (Barnett, 2001). With that said, let's look at the ninth and tenth amendment of the Bill of Rights: "The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people" (Ninth Amendment, n.d.) and "The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people" (Tenth Amendment, n.d.).
When addressing the federal government's ban on marijuana it's important to keep these points in mind. Commerce meant trade, either with foreign nations, among the states and with the Indian tribes. It didn't mean gainful activity, such as selling marijuana within a State. This is absolutely outside the bounds of the federal government's authority to regulate. If a State wants to allow marijuana to be purchased, sold and possessed, it is that State's Tenth Amendment right. If marijuana is being produced and sold within a State and not nationally, then the Federal government has no right whatsoever to be involved in the process.
Additionally, when analyzing the Gonzales v. Raich case, not only was there absolutely NO interstate trade of the marijuana in question, it was grown for medicinal use by the defendant. There was no commerce involved. The Commerce Clause does not give the Federal government the authority to restrict what plants Americans can grow, what medicine they can produce for themselves or use. The seizure by the DEA of this woman's marijuana was an overreach of federal power and arguably a violation of the Ninth and Tenth Amendments.
Lastly, the American system of government was established as a grand experiment. Each state was an individual experiment in government that would fail or succeed on their own. The successful states would be emulated by the other states and the ones who failed would serve as an example to the others of what not to do. A major benefit of this experiment is that failures are contained on a state level, leaving the other states intact. We have 50 such experiments spread across this great nation. When we allow the Federal government to regulate every state, our experiment will succeed or fail nationally. It is a lot more risky to have National programs, because if they fail the pain is spread around equally, there is no safe haven. I often use the example of lab rats. If you were a scientist conducting an experiment, would you use one lab rat or fifty? The answer is obvious.
Ivers, G. (2013). Constitutional law: An introduction. San Diego, CA: Bridgepoint Education, Inc.
Barnett, R. (2001, January 1). THE ORIGINAL MEANING OF THE COMMERCE CLAUSE. Retrieved January 9, 2015, from http://www.bu.edu/rbarnett/Original.htm
Ninth Amendment. (n.d.). Retrieved January 9, 2015, from http://www.law.cornell.edu/constitution/ninth_amendment
Tenth Amendment. (n.d.). Retrieved January 9, 2015, from http://www.law.cornell.edu/constitution/tenth_amendment