Marijuana and Prioritizing Resources

I never smoked pot, so you might expect I'm dubious of the medical marijuana laws passed by some states.  It seems to me likely these, whatever their benefits to the ill, will serve as figleaves (spell check doesn't like that) for abuse.  So I'm not applauding the Obama administration's ruling that DOJ won't spend time prosecuting those who use the laws.  On the other hand, I'd much rather DOJ devote its attorneys to prosecuting tax fraud and those who try to cheat the farm programs. So, as usual, I end up ambivalent.