Mexico has already militarized its law enforcement (and as far as I know, welcomes donations of military equipment), and what Hillary! alluded to was an undertaking similar to US/Columbia joint military efforts.
At any rate, "border security" and "using US military to eradicate Mexican organized narco-crime, in Mexico" are different approaches to a common problem.
I suggest anything is better than the executive policy of providing criminals along the border and in Mexico with automatic weapons, as was done by Obama-Holder -— first covered up, then lied about and now they remain silent on those actions.