Senators Booker and Warren call upon DOJ to "decriminalize cannabis using its existing authority"

As reported here, two notable US senators "are urging Attorney General Merrick Garland to decriminalize marijuana on his own" by "asking Garland and Department of Health and Human Services Secretary Xavier Becerra to use powers granted them under the Controlled Substances Act to deschedule — or decriminalize — marijuana at the federal level." The letter to this effect from the desk of Senator Elizabeth Warren and joined by Senator Cory Booker is available at this link, and it starts this way:

We write to urge the Department of Justice (DOJ) to decriminalize cannabis using its existing authority to remove the drug from the Federal controlled substances list. Under the Controlled Substances Act of 1970 (CSA), the Attorney General can remove a substance from the CSA’s list, in consultation with the Secretary of Health and Human Services (HHS).  Decriminalizing cannabis at the federal level via this descheduling process would allow states to regulate cannabis as they see fit, begin to remedy the harm caused by decades of racial disparities in enforcement of cannabis laws, and facilitate valuable medical research.  While Congress works to pass comprehensive cannabis reform, you can act now to decriminalize cannabis.

The letter goes on to explains the DOJ descheduling process this way:

The executive branch has the authority to initiate the process of cannabis descheduling.  The CSA empowers the Attorney General to initiate proceedings to reschedule or deschedule a drug, either individually or at the request of the HHS Secretary or another interested party.  The Attorney General then seeks a scientific and medical evaluation from the HHS Secretary, including the Secretary’s recommendations as to the appropriate scheduling for the drug or whether the drug should be descheduled.  If the Secretary recommends descheduling a drug, that recommendation is binding on the Attorney General.  However, if the Secretary recommends retaining a drug in the same schedule or moving it to a different schedule, that recommendation is not binding and the Attorney General may still choose to initiate a rulemaking procedure to deschedule or reschedule the drug.