Why does the U.S./Mexican governments refuse to defeat the drug cartels?

Why does the U.S./Mexican government refuse to annihilate the drug cartels? These cartels are more of a threat to the U.S. than the Nazis ever were, hence the Nazis didn't make it over here! Law enforcement on both sides of the border is a joke. Literally. Why can't they use the same tactics against the cartels that the cartels use against them and society? No method is too ruthless, murderous, inhumane or unacceptable for victory. Law enforcement should just start killing drug runners. Forget arresting people, just start killing them on the spot, they're smugglers. Prisons don't have unlimited space! Any cop who arrests a drug runner ought to be suspended without pay. This is war. Bring in the goddamn Air Force if we need to