In 2013, Manypenny introduced a bill to legalize marijuana in limited and medical cases. Manypenny believes that marijuana can be more effective and less harmful than currently-prescribed drugs to treat some conditions, including children with life epilepsy. He encountered opposition from other legislators who were concerned about the potential repercussions of state policy conflicting with federal policy, which outlaws marijuana. However, the August 2013 announcement by United States Attorney General Eric Holder that the federal government would not punish states for legalizing marijuana as long as the distribution was carefully regulated emboldened state legislators, including Manypenny. In September 2013, Manypenny told The Charleston Gazette that his chances for successfully forwarding this legislation in West Virginia has increased substantially.