Let’s see.

The US government decides to finally enforce immigration law. Illegals and their supporters riot all over LA and the Southwest. Local and State authorities are overwhelmed and Mexico eggs on the rioters. Washington sends troops to put down the riots. Mexico then invades the US. Takes control of the Southwest as Mexican territory and then launches an invasion right up to the Appalachians and burns and pillages everything they have taken. Under the “Russia is good” argument, Mexico is the good guy here too.