Some say that the United States is on a collision course with a serious crisis - that the nation is approaching this crisis at dangerously high speed and that the destructive potential of the inevitable impact is frightening to ponder. The crisis could slow the country's economic growth, weaken its national security, and undercut its efforts to compete successfully in global markets.
The crisis: Is it to come in the form of a dread disease such as AIDS? Will its roots lie in a chronic social problem, such as racial discrimination? No, this particular crisis is one of shortage, of supply and demand, and of demographics - reminiscent, in some ways, of the gasoline shortages of the 1970s, and the recent food shortages in the Soviet Union. In this case, though, the commodity in question is human. The next decade's shortage - we are told - will be one of...