Last week, Republican presidential candidates were asked about their positions on marijuana policy reform. While most of them responded that they would let states determine their own policies, they also stated their opposition to making marijuana legal for adults and revealed their serious misunderstandings of the relative harms of marijuana compared to alcohol and other drugs. Here is the portion of the debate concerning marijuana policy: https://www.youtube.com/watch?v=ns1njaMZKVs Vice's coverage…