Gallup: Americans Now Overwhelmingly Support Marijuana Legalizationselfnews Post Those in favor of legalizing cannabis surged 10 percentage points over last years Gallup poll to 58%. Gallup writes, The increasing prevalence of medical marijuana as a socially acceptable way to alleviate symptoms of diseases such as arthritis, and as a way to mitigate side effects of chemotherapy, may have also contributed to Americans growing support. 