Your answer is retreat.
No it is not.
My answer is to stand at the border and say "Welcome to America, here is your school house where english is spoken". And "This is Old Glory, and we salute it daily".
We need to crank up the assimilation machine that took in far more Italian, German and other immigrants back in the day when the US had no immigration quota whatever.
Unfortunatly the conservative side just wants mexicans to go away, and the left want's them to stay mexican because they think they can keep their vote Democrat.
Neither is a good option for conservatives, who should be more interested in welcoming good Catholic families who don't favor abortion into the Republican/American camp. Instead of balkanizing them like the left want's to do.