F or the past year and a half, the stewards of the American economy have been worrying that too many Americans are drawing regular paychecks. The fear is never quite put that way, of course, but as the national unemployment rate has dropped to 4 percent, the Federal Reserve has been getting restive. Six times in 15 months, the governors of the Federal Reserve Board have voted to raise interest rates, which is their way of saying the economic news is a little too good. The goal of this monetary tightening is to brake the economy, ideally bringing it to a "soft landing" of slower growth without recession. So far, under the leadership of Chairman Alan Greenspan, the Fed is moving cautiously, trying not to trigger an outright recession. Yet there are signs that higher interest rates are having some effect. Before this summer, national employment was increasing by an average of 251,000 jobs per month. In July and August, employment decreased by an average of 78,000 jobs. Since it takes...