The Mexican Consul General of Phoenix says that Mexican workers are leaving the U.S. in response to heightened immigration enforcement (stepped up raids and tough laws at the municipal level) but that in coming decades, the U.S. will be sorry it pushed out these young, able-bodied workers.

Speaking to the Thunderbird School of Global Management in Arizona, Carlos Flores Vizcarra said demographic estimates show that within 30 years, nearly 77 million Americans will retire:  "So the question is, who will take the place of those folks who are retiring?" he asked. Mexico is also facing a shortage of labor in coming decades, Flores added, and the U.S. will not find it easy to lure these workers back.

While everyone knows that low wages in Mexico  are partially responsible for the numbers of Mexicans leaving the country seeking work elsewhere, the population explosion south of the border also has been a factor, he said.  During World War II, Mexico had 18 million citizens; today, 20 million foreign-born residents of Mexican descent live in the U.S. --that's more than the entire population of the country in the 1940s.  And Mexico's population has quintupled, to about 107 million people.

"It's like a revolution that no country could have digested," Flores said. "What has been our safety valve? The U.S."

But Mexicans seeking a better climate for immigrants aren't just going back to Mexico, Vizcarra said. They're heading north to Canada.

"Canada is pressing on Mexico so that Mexico can provide more labor to Canda," he said. "From this moment, Mexico is looking to the Canadian horizon, maybe with more interest than to the U.S., basicaly because of the sluggish economy here in America, and also becuase Canada is discovering new economic frontiers in Manitoba and Alberta."