People have been trying get permission to use marijuana as a part of religious ceremonies for years now, with no luck. And yet, others have had success getting permission to use harder drugs like peyote and ayahuasca for religious purposes. Here's why.
First, let's break down the basis for religious freedoms in America. There are a number of laws on the federal and state levels that protect individual religious civil liberties. Under these laws, if a registered church believes that their religious freedoms are being restricted by the state, they can appeal to the courts for exemption from those restrictions. In the past, some organizations have convinced the courts that this means they should have access to drugs that would otherwise be illegal because they are important for to their religious beliefs.
For instance, Native Americans are allowed to use peyote and ayahuasca in religious ceremonies, even though both substances are prohibited under federal law in America. And groups like the Oklevueha Native American Church have even won the right for non-Indigenous people to participate in peyote ceremonies legally.
Despite this, no religious group has been successful in winning the right to use cannabis in religious ceremonies. That's regardless of the fact that cannabis does have legitimate sacred uses in belief systems like the Rastafari religion.
So why can Native Americans legally use peyote in religious ceremonies, but Rastas and other faith communities can't consume cannabis? The answer seems to come down to the different effects of the drugs. Consuming peyote and ayahuasca usually leads to a pretty intense and long-lasting psychedelic experience that can be quite uncomfortable, including episodes of vomiting and severe disorientation. That's why shamans are there to oversee their trip. Smoking cannabis, on the other hand, is a much less intense experience. The typically mellow high associated with marijuana means that federal authorities consider it more likely to be diverted for use in non-spiritual circumstances than something like peyote, which people probably wouldn't want to dabble with on a daily basis even if they could.
Basically, authorities are afraid that if they allow the use of cannabis as a sacred sacrament, they would effectively be opening up a legal and untaxed market for cannabis.
For more on marijuana and religion, check out Amanda Chicago Lewis's article on cannabis churches here.