U.S. defense primes are reporting impressive second-quarter earnings. General Dynamics, Lockheed Martin, Northrop Grumman and Raytheon all raised guidance for 2013, and their stock prices responded favorably. The bite of sequestration—automatic, across-the-board cuts in the Defense Department's budget—has initially proved to be not as harsh as was expected earlier in the year, and operating profits are benefitting from cost-cutting. Shareholders adore the primes' share repurchase

The automatic U.S. budget cuts known as “sequestration” went into effect on March 1, but the sky has not fallen as far as investors and traders are concerned. There is no pure defense stock-price index but shares of the largest U.S. defense primes have outperformed both the S&P 500 and Dow Jones Industrial Average since March 1. Small and mid-size stocks have also performed well and even the major U.S. defense services contractors—Booz Allen, CACI, ManTech and SAIC—have seen their shares appreciate more than broader market indices.

As he was recently discussing the pivot of U.S. strategic emphasis to the Asia-Pacific region, Deputy Defense Secretary Ashton Carter repeated an assertion that the U.S. spends more on defense “than the next 16 largest militaries combined.” While Carter's talking point is more or less technically correct, such a comparison does not indicate what an appropriate level of spending should be. A more useful way to think about U.S.