WE'RE pleased to see Foreign Policy's blog Passport popularising the "sunk costs fallacy".  The most rational decision is always the one that will produce the best result in the future, not necessarily the one into which you've already ploughed lots of money, time or soldiers' lives.

But is Passport right that this passage from the State of the Union address represents the fallacy?

Yet it would not be like us to leave our promises unkept, our friends abandoned, and our own security at risk. (Applause.) Ladies and gentlemen: On this day, at this hour, it is still within our power to shape the outcome of this battle. Let us find our resolve, and turn events toward victory.

Failing to keep promises, foreign-policy realists will convincingly argue, can hurt future credibility—only a tenuous connection with sunk costs.  And abandoning friends and risking one's own security are bad ideas in almost any circumstances, and have nothing to do with sunk costs.

For a better example of Bush's use of the sunk costs fallacy, see here.  And do go read Foreign Policy's recent article Why Hawks Win, which introduces several other common and harmful, deeply-rooted fallacies.