Utah Sen. Mitt Romney and other Republican senators are raising concerns about a recommendation from the Biden administration to reschedule marijuana from a drug seen as having no accepted medical use and a high potential for abuse to one considered at low risk for dependence.

In a letter to federal Drug Enforcement Administrator Anne Milgram, Romney and fellow GOP members of the Senate Foreign Relations Committee, Sens. Jim Risch of Idaho, and Pete Ricketts of Nebraska, questioned whether shifting marijuana from a Schedule I to a Schedule III controlled substance would violate an international treaty.

“Any effort to reschedule marijuana must be based on proven facts and scientific evidence — not the favored policy of a particular administration — and account for our treaty obligations,” the senators wrote, citing the DEA’s duty to ensure compliance with the Single Convention on Narcotic Drugs, ratified by the Senate in 1967.

Inside Utah’s medical marijuana program

“In prior rescheduling proceedings, the DEA has determined that section 811(d) requires it to classify marijuana as a schedule I or II drug in order to comply with our treaty obligations under the Single Convention,” the senators’ letter continued, referring to a section of the treaty.

“It is important that the DEA continues to follow the law and abide by our treaty commitments,” the senators wrote, asking the DEA for a response by April 12 to a list of questions, such as the impact rescheduling could have on whether other countries continue to enforce treaty controls, “including for deadly narcotics like fentanyl.

Romney posted on X, formerly known as Twitter, “To be blunt: rescheduling marijuana may cause the U.S. to violate obligations under the Single Convention on Narcotic Drugs. Efforts to reschedule marijuana must be based on evidence, not politics, and @DEAhq must ensure we abide by our treaty commitments.”

Marijuana is controlled under the treaty, the letter points out, “which is not surprising given its known dangers and health risks — and the United Nation’s International Narcotics Control Board (INCB) has fiercely criticized efforts to legalize marijuana in other countries as a violation of the treaty.”

The letter states that last month, a study associated daily marijuana use with a 25% increase in the risk of heart attack and a 42% increase in the risk of stroke, and that other studies have linked the use of marijuana “with serious psychotic consequences, including schizophrenia and bipolar disorder.”

Despite marijuana being illegal under federal law, most Americans now live in a state that has legalized the drug and most also have at least one cannabis dispensary in their county, according to an analysis by the Pew Research Center released in February.

Utah’s new medical marijuana program more popular than officials expected

As of February, the recreational use of marijuana is legal in 24 states and the District of Columbia, according to the Pew Research Center, while another 14 states, including Utah, allow the drug for medical use only. Colorado and Washington were the first states to legalize recreational marijuana use, in 2012.

Last August, the U.S. Department of Health and Human Services recommended to the DEA that marijuana be rescheduled from a Schedule I drug, like heroin or LSD, a Schedule III drug, a recommendation the agency said was based on a federal Food and Drug Administration review requested by President Joe Biden in 2022.

Schedule III drugs include ketamine, anabolic steroids and some acetaminophen-codeine combinations and are still controlled substances under federal law. The Associated Press reported that it is unlikely state medical marijuana programs “would meet the production, record-keeping, prescribing and other requirements for Schedule III drugs.”

Rescheduling marijuana is seen as making it easier for researchers to study the drug, according to the AP, but wouldn’t affect the banking issues associated with the legal sale in some states of a federally controlled substance.