Duke University professor John Lewis offers this perspective in the Fall 2011 issue of The Objective Standard: "9/11 Ten Years Later: The Fruits of the Philosophy of Self-Abnegation".
In medicine, too often patients will succumb to otherwise-survivable diseases because they lack sufficient will or desire to live.
The same is true of civilizations. If a civilization lacks the equivalent of a healthy "self-esteem" and instead internalizes the cultural equivalent of "self-contempt", then it may not really think it deserves to survive when challenged. Whether 21st-century America falls in that category remains to be seen...