How the War on Drugs has intervened in the US-Mexico security relationship

The US-Mexico relationship is problematic when viewed from a security studies viewpoint. Here, US behaviour towards Mexico seems inconsistent. Why, for example, does the ‘war on drugs’ seemingly take precedent over Mexican domestic stability? In a similar vein, Mexico is the third biggest energy supplier to the US, yet rarely features in the energy security discourse in the way that distance threats such as Iraq and Iran do. How can we reconcile this outwardly contradictory hierarchy of strategic priorities through a security lens?