Defendants were convicted in the Municipal Court of driving with an impermissible drug or its metabolite in a person’s body. Defendants appealed. The Superior Court, Maricopa County affirmed. Defendants sought special action review and The Court of Appeals denied relief. Defendants sought further review, and the Supreme Court of Arizona agreed to hear the case.

The Arizona Medical Marijuana Act (“AMMA”), passed by voters in 2010 and codified as A.R.S. §§ 36–2801–2819, allows a person who has been diagnosed by a physician as having a debilitating medical condition to apply for a card identifying the holder as a registered qualifying patient. Such patients may possess and use limited amounts of marijuana for medical reasons. The AMMA broadly immunizes them from prosecution for using medical marijuana consistent with the Act.

Arizona’s laws generally make it a crime for a person to drive with any amount of certain drugs, including marijuana or its impairing metabolite, in the person’s body. We today hold that the AMMA does not immunize a medical marijuana cardholder from prosecution under § 28–1381(A)(3), but instead affords an affirmative defense if the cardholder shows that the marijuana or its metabolite was in a concentration insufficient to cause impairment.

I.

Kristina Dobson and Marvelle Anderson (“Petitioners”) were each charged with two counts of driving under the influence

(“DUI”) . . . Blood tests showed that each Petitioner had marijuana and its impairing metabolite in his or her body.

. . . The AMMA broadly immunizes registered qualifying patients for their medical use of marijuana, providing:

A registered qualifying patient . . . is not subject to arrest, prosecution or penalty in any manner, or denial of any right or privilege, including any civil penalty or disciplinary action by a court or occupational or professional licensing board or bureau: (1) For the registered qualifying patient’s medical use of marijuana pursuant to this chapter, if the registered qualifying patient does not possess more than the allowable amount of marijuana.

This grant of immunity is not absolute. For instance, the AMMA does not prohibit prosecution for “[o]perating, navigating or being in actual physical control of any motor vehicle, aircraft or motorboat while under the influence of marijuana.” However,

“a registered qualifying patient shall not be considered to be under the influence of marijuana solely because of the presence of metabolites or components of marijuana that appear in insufficient concentration to cause impairment.”

. . . A qualifying patient may be convicted of an (A)(3) violation if the state proves beyond a reasonable doubt that the patient, while driving or in control of a vehicle, had marijuana or its impairing metabolite in the patient’s body. The patient may establish an affirmative defense to such a charge by showing that his or her use was authorized by the AMMA . . . and that the marijuana or its metabolite was in a concentration insufficient to cause impairment.

The patient bears the burden of proof on the latter point by a preponderance of the evidence, as with other affirmative defenses.

Petitioners made no effort to show that the marijuana in their bodies was in an insufficient concentration to cause impairment.

Instead, they argued that the AMMA categorically barred the (A)(3)

charge, and they offered only their respective registry identification cards into evidence . . . Any error by the trial court in excluding evidence of the registry cards was harmless in light of the stipulations by Petitioners that they had marijuana in their bodies while driving (blood tests revealed both THC and its impairing metabolite hydroxy-THC) and their failure to offer any evidence that the concentrations were insufficient to cause impairment.

. . . Rather than shielding registered qualifying patients from any prosecution under A.R.S. § 28–1381(A)(3), the AMMA affords an affirmative defense for those patients who can show, by a preponderance of the evidence, that the concentration of marijuana or its impairing metabolite in their bodies was insufficient to cause impairment. We vacate the opinion of the court of appeals and affirm the Petitioners’ convictions.

Questions:-

1. Thinking specifically about DUI, should marijuana and alcohol be treated the same?
2. Recreational marijuana is legal in several states. What remains illegal in those states?