The crux of the argument for increased immigration by Mr. Bush and Clint Bolick (his co-author of a forthcoming book on “Immigration Wars”) is that the economy and social-welfare system will collapse without increased immigration. They write:

The birthrate in this country has fallen below the level necessary to sustain the population at the very time that millions of Americans are leaving the workforce and expecting retirement benefits. The nation needs energetic young workers to spur the economy and support an ever-increasing social-welfare burden.”

When you read about a falling birthrate and a dearth of workers, the words PONZI SCHEME should start flashing in your mind. The average annual number of births between 2000 and 2009 was more than four million. The population grew by about 2.8 million a year over the same period. The U.S. is currently issuing more than a million new green cards a year and admitting about as many long-term temporary foreign workers. But that is not enough to satisfy employers.

It’s true that as baby boomers retire the country is experiencing a transition in which the ratio of retirees to workers has increased in proportion to the number of those working. But pumping more foreign workers into the economy will only perpetuate the problem as those foreign workers age and retire. Like a Ponzi scheme, this can’t work indefinitely because sustaining a population requires resource inputs – food, water, non-renewable resources – and, therefore, has a limit.

When a Ponzi scheme collapses, those who have invested in it suffer. If the endless population expansion advocates have their way, the collapse will come when non-renewable resources – think petroleum and other energy resources are depleted and aquifers are pumped dry – and, at that point the loss will not be an economic investment, but something far worse.