[SpinnerWebb]

Enosh: It is warfare if the Mexican soldier was acting on orders to invade the United States, which is unlikely.

mojito: The truth of the matter is that the government of Mexico is losing control over their armed forces.

I will disagree with Enosh, and agree with mojito on this one. If the government has lost control of it's army to the Cartels, then they have surrendered to a de facto coup d' tat. The Cartels now are using their hired army to engage in activity on our sovereign soil, which the Citizens of the United States have deemed illegal to engage in. Political, Financial, or otherwise, that's an encroachment to our sovereignty and needs to be addressed, with force if necessary.

[Enosh]

“If the government has lost control of it’s army to the Cartels,...”

In that case he would indeed represent an armed force acting on behalf of a hostile agent, subject to be shot on sight.