Comment: Perhaps if we deal with drug addiction as a mental & physical illness instead of criminal activity, the addicts will not waste our $$$ or their time being incarcerated instead of rehabilitated; other nations found this quite effective.  But as you know, the private prison lobby is quite powerful and has many key legislators in their pocket. 
If you really wish to find the gateway drug, its alcohol.  Its much more readily available and has been well documented to be a truly addictive drug.  
Hopefully you will see the medical benefits of marijuana.
"When followers of a particular sect enter into commercial activity as a matter of choice, the limits they accept on their own conduct as a matter of conscience and faith are not to be superimposed on the statutory schemes which are binding on others in that activity." (1992 opinion on US v Lee 1982).  This forum isn't conducive to lengthy discussion; Scalia obviously shifted crazy right after this.  You couldn't find this in your search???