The warning comes as voters in Maryland, Arkansas, and three other states gear up to decide in next month s midterm elections whether to allow recreational weed for residents aged over 21.
More than two thirds said they backed legalizing the possession of small amounts of pot for personal use, and Joe Biden s pardons for people convicted on federal possession charges.
The survey is the latest indicator of growing tolerance for the drug, as voters in five states gear up to decide whether to allow recreational weed for residents aged over 21.
Efforts to end the federal prohibition on marijuana have fizzled, but polling released on Wednesday shows that three in five voters support a bill and wanted weed legalized nationwide.