The world’s only superpower, the Great Hegemon and mightiest military force now, then or ever, is cranking up to end the invasion of its land by hundreds of thousands of undocumented workers from Mexico. President Bush cannot send in the Marines because they’re busy elsewhere, but he does have the National Guard–exhausted, without equipment, raggle-taggle and overused. He nevertheless has decided to dispatch them to patrol our borders.

Not so fast. There may be no need. The latest demographic news is that Mexicans may have stopped reproducing in sufficient numbers to satisfy America’s need for cooks, maids, gardeners and low-wage laborers and a near-infinity of other occupations.

The Wall Street Journal, often the first to get on to such things, reports that “Thanks to a decades-long family-planning campaign, most Mexicans are having far fewer children than was typical a generation ago.” In 1968, the paper reports, “the average Mexican woman had nearly seven children. Today, the figure is just above two, comparable to the US.”

The newspaper opines that “Mexico’s new demographics could have a big impact on the US. Although the flood of Mexicans heading north is whipping up debate in Washington, the crossings may slow in future decades. That could happen simply because smaller families limit the pool of potential migrants. A slowdown would be especially likely if a growing middle class makes more Mexicans comfortable at home and averse to risking a dash across the border.”

So the day may not be far off when the Mexican middle class will be intercepting Guatemalans on their way north to give them jobs cleaning swimming pools and hospital corridors in Mexico. Imagine: a shortage of Mexican workers. Next thing you know Bush will be sending the National Guard across the Rio Grande to kidnap them instead of trying to keep ’em out.

It’s an odd situation. While we worry about the overpopulation of the planet by homo not so sapiens, acute people shortages are cropping up all over the globe. Just the other day the New York Times reported that President Vladimir Putin directed Parliament “to adopt a 10-year program to stop the sharp decline in Russia’s population, principally by offering financial incentives and subsidies to encourage women to have children.”

Well, Putin might issue such orders, since Russia’s population is declining at the rate of 700,000 per year. This is no joke, given that their computer programmers are as good as any to be had in India. Moreover, Russia is a prime supplier of fuel to Western Europe and of gangsters and sex workers to the United States.

The Times article went on to relate that “Mr. Putin said, ‘Now, the main thing, what we see as the main thing–‘ and he was interrupted by a call from the floor.

” ‘Love!’ the voice said.

” ‘Right,’ Mr. Putin answered.”

But love may not be enough. The Russians may already be doomed. The Russian male barely lives longer than a fruit fly, which may have something to do with his being drunk much of the time. Anyhow, what with sickness, early death, immigration, mistreatment by government and pessimism, there probably are not enough young fertile women left in the country to reverse the tide. Let that be a lesson to native-born Americans, who barely manage to reproduce themselves.

Prosperity can push a nation’s people along to extinction just as easily as war, disease and abuse. Rich countries like Australia, Singapore, Japan and France are paying couples to have children. So are not-so-rich countries like Poland and Italy.

In these places, where the government and the superrich do not kick people around or feed them cabbage leaves, people stop having children when they realize that kids are an economic impediment. Children may be a joy but apparently not as much of a joy as regular vacations to fancy places, four-star dining and a house in the country. Nor is procreation helped by TV shows informing people the choice is between having kids or having enough money to retire.

So, all you folks who decided it was more fun to go skiing and drive a BMW than have a kid, when you’re old, who is going to wipe your chin and help you into your wheelchair? Remember, the guest worker you keep out today is the one you’ll wish you had welcomed tomorrow.