Mexico has been invading the US illegally for many years. But without arms, without armies, and with only covert governmental support from Mexico. What kind of President wants its population to leave their country? The East Germans used to dig tunnels to get out, but Mexicans are digging tunnels to get into the US.
In recent years, their armed forces have been engaged in this invasion, behind the scenes. Thanks to the blogs, this quiet war is getting some attention. The MSM ignores it, due to psychotic political correctness or something like that. Kind of similar to the Moslem invansion of Europe.
My suggestion is that Mexico get its act together, and become a country people want to live in and stay in. Why can't they do that? No-one is stopping them, and the US does all it can to help them. They have natural resources, great beaches, good hunting, a big population of nice folks, religion, a work ethic - everything you need to make a proud, successful nation without trying to colonize the US. (We tried being colonies already, and we did not like it very much.)
Message to the invaders, and legal immigrants too from around the planet: Why not stay in your own country, and make it a better place? It's not like the 1920s anymore - there is a world economy and the internet, and we are all connected. Show some pride of homeland - some patriotism. You can do it. Everyone in the world who wants to breathe freedom and who wants to take the risk of economic opportunity and personal development and achievement instead of being weak dependents of a totalitarian or corrupt or socialist State, wants to come to the US. We only have room for a few of you brave good people, and it is a big loss for your home country to have the ambitious and most energetic folks walk away.
Why should the US and Australia be the only Meccas for those excellent, energetic people seeking such fine but difficult things? Be patriots, honor your own traditions, and fix your own place. We did it here. India is doing it, too, Vietnam, even Libya - of all places - among others. It is not easy. For us, it required a war or two or three, but we paid our dues. It is worth the effort.