There is a huge gulf (ocean) in motivation between trying to bring "democracy" to third world countries and an attack on the country's doorstep. When only 1 DEA agent was murdered in Mexico, it provoked an enormous response.[0]

There's a great line at the end of Tora! Tora! Tora! from Admiral Yamamoto that would undoubtedly apply in such a scenario, "I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve."

[0] https://en.wikipedia.org/wiki/Kiki_Camarena