Mexico has no idea what they have started.
Mexico needs the US a lot more than the reverse.
The only real leverage they have is Oil, which we can do without, once the Keystone pipeline is active; Oil is fungible, and transportation costs astronomical.
Imagine Mexico with zero American tourism; No illegal worker funds going south.
What are they gonna do, arm their drug cartels and ship them north?
I love the Mexican people. In Mexico.
I visited several times a year between 1993 and 2001.
I am fluent in Spanish, but avoided using it the last few years I visited. The conversations I overheard as a dumb gringo, and the reports of (really stupid) permanently missing Americans, finally convinced me my family and I had more chance of surviving vacations closer to home.
“arm their drug cartels and ship them north?”
They already did that-they are all in the Juarez/El Paso, and Laredo areas-I rarely visit family in rural W/SW Texas these days...