She's really retiring as a result of her MS. Since medical marijuana is already legal in Michigan, she's not really campaigning for that, she's campaigning for straight up legalization. On that, I hope she is not successful. Most people, including me, are loathe to deny anyone with an identifiable medical issue anything that may alleviate their discomfort, but this need not extend into general marijuana use.
I hope the research that has already resulted in many treatments that have improved the health of those afflicted with MS results in a cure. I do wish her the best with her health, just not with what she is supporting regarding marijuana.