In news coverage of last week’s Department of Justice memo, there was a lot of confusion over exactly how many states have medical marijuana laws. Some outlets reported that 14 states have such laws. Others said 13 states. So which is it? And why the confusion? The answer is 13. They are Alaska, California, Colorado, Hawaii, Maine, Michigan, Montana, Nevada, New Mexico, Oregon, Rhode Island, Vermont, and Washington. But many media—as well as some government sources—incorrectly counted Maryland as…