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The Supremacy Clause and Marijuana

Andrew Kennard
3 min readFeb 20, 2021


At the Constitutional Convention of 1787, the Founders created a new, stronger national government to replace the Articles of Confederation. The Constitution included the “supremacy clause,” which declares that “the laws and treaties of the United States are supreme throughout the land” (Kollman 51). The general idea is that states are not allowed to have laws that directly counteract federal laws.

Enter the curious case of marijuna legislation. Many states have either fully legalized marijuana or legalized it for medical use (see the link below for a full map). However, marijuana use is a federal crime.

This situation seems pretty untenable: logically, it would seem that the supremacy clause should keep the states from enacting laws that legalize marijuana. However, I took a look at a Congressional Research Service report (see below), and here’s what I took away:

1.The Supreme Court held that “‘the question of preemption is one of determining congressional intent” in Skull Valley Band of Goshute Indians v. Nielson in 2004.

2. The Controlled Substances Act (which causes the federal ban of marijuana) says that the Act is not intended to strike down state laws unless they make it impossible for a person to comply with both state law and the CSA OR the state law keeps the CSA from having its intended effect.

a. “The Supreme Court has consistently held that that there is no basis to imply impossibility preemption where a state simply permits what the federal government prohibits” (See, Wyeth v. Levine, 555 U.S. 555 (2009)).

b. Although there are arguments to be made about state laws keeping the federal ban from having its intended effect, the federal government can still enforce its own law in states that allow for marijuana use. A state law that protected marijuana use from federal prosecution would probably be preempted by federal law.

3. While marijuana use is a federal crime, prosecution for marijuana use has not been much of a priority for federal law enforcement in the past in cases when the person in question is in compliance with state law, at least in regards to medical use of marijuana.

4. An interesting quote that caught my eye: “Arguably, then, the preemptive effect of the CSA is not as broad as congressional authority could have allowed.”

A brief note: the report I read does deal with medical marijuana exceptions, perhaps because it is from 2012. I don’t think it addresses state laws that allow for recreational use, but while medical marijuana exemptions are more likely to be protected, I think that my points would still stand.

As I understand it, there isn’t a conflict between the CSA banning marijuana and state laws allowing marijuana because the state laws do not force anyone to use marijuana nor they do not keep the federal government for prosecuting anyone for using marijuana.

I hope this was helpful. If you want to learn more about this or about past federal enforcement of marijuana violations, there’s more information in the white paper below.


Kollman, Ken. The American Political System. 3rd ed., W. W. Norton & Company, Inc., 2017.

A white paper on the subject from



Andrew Kennard

Christian, writer, Eagle Scout, and Drake University Class of '24.