It took until the end of July for Sessions to officially respond to Hickenlooper, though he's made plenty of statements in the interim and even met with Hickenlooper and Governor Jay Inslee of Washington. In his response, Sessions cites rising out-of-state diversion of marijuana, youth use, emergency-room visits and traffic deaths related to marijuana as cause for "serious questions." The stats he used, however, were from the Rocky Mountain High Intensity Drug Trafficking Area Report, a report that has drawn criticism for its data-collecting and presentation methods.
In his letter, Sessions also questioned the power of the Cole Memorandum said that the Department of Justice's authority to enforce federal law in states that have legalized marijuana remains unaltered.
After receiving the letter, Hickenlooper's office promised to provide "a comprehensive response." That response went out on August 24, and it's indeed comprehensive, signed by both Hickenlooper and Colorado Attorney General Cynthia Coffman:
Here's hoping that Sessions takes his duty to enforce states' rights equally seriously.