USA Today:  “Three states will vote Nov. 6 on whether to allow recreational use of marijuana. There’s still a federal prohibition, and approval would surely bring court challenges.  Now that medical marijuana is permitted in about one-third of the nation, advocates hope to move beyond therapeutic uses with ballot questions in three states that could legalize pot for recreational use.  Voters in Colorado, Washington state and Oregon face proposals to change state laws to permit possession and regulate the sale of marijuana — though the plant with psychoactive properties remains an illegal substance under federal law.