Eric Sevareid (1912-1992), the author and broadcaster, said he was a pessimist about tomorrow but an optimist about the day after tomorrow. Regarding America's economy, prudent people should reverse that.

This week, according to the Financial Times' Robin Wigglesworth and Nicole Bullock, "the U.S. stock market will officially have enjoyed its longest-ever bull run" — one that rises 20 percent from its low, until it drops 20 percent from its peak. And Sept. 15 will be the 10th anniversary of the collapse of Lehman Brothers, the fourth-largest U.S. investment bank. History's largest bankruptcy filing presaged the October 2008 evaporation of almost $10 trillion in global market capitalization.

The durable market rise that began March 6, 2009, is as intoxicating as the Lehman anniversary should be sobering: Nothing lasts. Those who see no Lehman-like episode on the horizon did not see the last one.