From this morning's Wall Street Journal:

...Yesterday's new Dow Jones high is nonetheless worth celebrating as a sign of America's economic resilience. At the start of every bear market, there are always voices saying we will never see the top again. But the smartest investors always turn out to be those who see new lows as a buying opportunity.

In the current mini-bull market, stocks have been driven by a record 13 straight quarters of double-digit gains in corporate earnings. With more of the same expected this year and next, many stocks have price earnings ratios that make them good targets for "value" investors.

The stock market's strength is an especially good omen given that we are at a point in this expansion when many economists doubt its staying power. Investors seem to be betting that rising rates, the housing slump and a possible change of power in Congress won't stop the economy's growth. They may well be wrong in the short term. But the lesson of yesterday's new stock market high is that in the long term optimism always pays.