Someone once told me the one thread that runs through them all is a premium on personal courage - not intellectual courage, but just plain physical courage.

Lord’s remark distinguishes between two kinds of bravery: the courage to hold unpopular ideas (“intellectual courage”) and the more immediate willingness to face bodily danger (“plain physical courage”). By calling physical courage the “one thread” running through “them all,” he implies that across the episodes or people under discussion—typical of Lord’s narrative histories of crisis—what most consistently determines action is not brilliance or argument but the capacity to act under threat. The quote also carries a note of secondhand authority (“Someone once told me”), suggesting Lord is passing along a hard-earned generalization about human behavior in extremis: in decisive moments, character is revealed less by what one thinks than by what one can bring oneself to do.