Americans are glum at the moment. No, I mean really glum. In April, a new poll revealed that 81 percent of the American people believe that the country is on the "wrong track." In the 25 years that pollsters have asked this question, last month's response was by far the most negative. Other polls, asking similar questions, found levels of gloom that were even more alarming, often at 30- and 40-year highs. There are reasons to be pessimistic—a financial panic and looming recession, a seemingly endless war in Iraq, and the ongoing threat of terrorism. But the facts on the...