It's long been the dream of some activists and their intellectual allies, and it is coming true because of the current recession or economic downturn or whatever you want to call it:

Illegal immigrant Mexican workers are leaving this country in droves, crossing the border north to south and going back home. Some are already coming back because things are even tougher in Mexico, but so far, not most.

The reasons are many, including increased enforcement activity against American employers who hire illegals and more cooperation from local police in various parts of this country.

But economics are the main reason immigrants are leaving. As more companies cut budgets and banks foreclose on many thousands of homes, employment opportunities for unskilled illegal immigrants have diminished.

Over the last 18 months, according to Carlos Flores Vizcarra, the Mexican consul general in Phoenix, more than 2 million Mexican immigrants have returned home because of diminished opportunities here. That amounts to about 10 percent to 12 percent of all illegals who were in this country two years ago.

It may be the realization of a fantasy for the anti-immigration lobby, but it also might be a hint of a nightmare to come for other people and businesses. For one thing, farmers in many parts of America complained both of the last two years of a labor shortage. Whether or not it's coincidence, the prices of many foodstuffs rose steeply during that time and they're still going up.

And homeowners who are staying put may soon be paying more for roofing, fencing and many other chores long performed by Mexican migrants. Not to mention the prices of restaurant meals, hotel rooms and car washes, to name three industries also known to employ many illegals.

The suggestion these things may be harbingers of the not-to-distant future comes in some remarkable demographic information Flores disclosed this fall in an unpublicized but significant speech to students at Arizona's Thunderbird School of Global Management.

"Mexico will not be a never-ending source of human beings as it has been for the last 60 years," Flores said. "There will be shortages of labor in Mexico." If he's right and Mexico does experience its first-ever labor shortage, Mexican workers here almost certainly will return home in numbers far larger than those of the last two years.

Why a labor shortage in a nation that has long suffered massive unemployment, driving would-be workers to risk the dangerous migration to this country?

Flores said the population increases Mexico has seen since the early 1940s are ending. In 1942, when America began sending large numbers of its young men to war overseas and Mexicans moved in behind them to do essential work both illegally and under the old bracero guest worker program, Mexico had only 18 million persons in a territory almost half as large as America. Today, population exceeds 107 million, a five-fold increase in just over 60 years. The huge and fast Mexican population explosion "is like a revolution that no country could have digested," Flores said. "What has been our safety valve? The USA."

In short, Mexico had no room for the approximately 22 million migrants living in America during the peak of the illegal immigrant boom earlier this decade. America did.

But internal Mexican projections now indicate population is stabilizing, with forecasts that the number of Mexicans will actually begin dropping after about 2040.

In short, the end is in sight for the population explosion that created masses of immigrants and a seemingly endless supply of cheap labor for America. At the same time, prosperity in Canada and a strong Canadian dollar are drawing more and more Mexican workers there, providing new competition for Mexican workers.

Which led Flores to ask this: "Within 30 years, nearly 77 million Americans (known as the Baby Boom generation) will be retiring. Who will take the place of those folks in the work force?"

No one knows just now, but the presumption long has been that it would be immigrants, with Mexico the most obvious likely source. But no one knows what might happen if that labor source dries up.

Which is a completely new scenario for the anti-immigration lobby to ponder.

Thomas D. Elias is a syndicated columnist on California issues.

(Nov. 11, 2008)