"Probable Cause to Believe What? Partial Marijuana Legalization and the Role of State Law in Federal Constitutional Doctrine"

The title of this post is the title of this notable new article authored by Kevin Cole now available via SSRN. Here is the abstract:

When simple possession of marijuana was invariably illegal under state law, a dog alert or a police officer’s own perception of the scent of raw or burnt marijuana sufficed to permit a search for the source of the scent.  As states went beyond decriminalization to legalize possession, for medical or recreational use, the smell of marijuana became less probative on the question of whether the state’s laws were being violated.  

But even in legalization states, courts have upheld an officer’s right to search a car upon detecting the scent of marijuana.  The courts’ explanations have been analytically troubling. Analyzing the problem is complicated by more general phenomena: the Supreme Court’s reluctance to specify in greater detail the nature of the probable cause requirement, and the Court’s differing approaches to the significance of state law in federal constitutional doctrine.