One of the points regarding security that I seem to be hearing with growing frequency is that Mexico simply doesn't spend nearly enough to be serious about improving its crime-fighting institutions. This figure certainly furthers that argument: according to the Stockholm International Peace Research Institute, Mexico has the lowest military spending as a proportion of GDP in all of Latin America. Chile, for instance, spends roughly eight times per capita what Mexico does on the armed forces, Colombia almost five times, Brazil more than three times. If there was a stronger Federal Police taking the lead in Mexico, if the government wasn't relying so heavily on the military, that wouldn't be a problem. But to ask the military to do more with less is just a recipe for ineffectiveness, regardless of your opinion of the wisdom and legality of using the military to start with.
Update: Noel Maurer had a lot more on this in November.