"Which causes more cancer, cannabis or its prohibition?"

Vivian McPeak (seattlepi.com-op/ed):

In 2009, there were roughly 858,400 arrests for cannabis in the United States. 758,000 of those arrests were for simple possession of the herb. Interestingly, in that same year only 581,000 Americans were arrested for violent crimes.
(Source: "Crime in the United States 2009," FBI Uniform Crime Report)

(SNIP)

The largest study looking for a link between cannabis and cancer concluded that even regular, chronic smokers of pot do not develop cancer. The study was done by University of California pulmonologist, Dr. Donald Tashkin, who said:

We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use. What we found instead was no association at all, and even a suggestion of some protective effect.

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