Over the past 200 years, the stock market's steady upward march occasionally has been disrupted for long stretches, most recently during the Great Depression and the inflation-plagued 1970s. The current market turmoil suggests that we may be in another lost decade.

The stock market is trading right where it was nine years ago. Stocks, long touted as the best investment for the long term, have been one of the worst investments over the nine-year period, trounced even by lowly Treasury bonds.

The...