The decade that just ended saw a period of uninterrupted economic growth. In the decade to come, we'll pay for squandering it. Since the so-called Great Recession officially ended in the third quarter of 2009, the United States has enjoyed 42 consecutive quarters of solid if unspectacular economic growth. That's the longest run of uninterrupted growth since government economists began tracking the business cycle in the 1850s, far outpacing the average economic expansion of 18 months. Employment has increased by 12 percent, the jobless rate reached record lows, and America's gross domestic product (GDP) has increased by more than 25...