長久以來，學術界對於恐怖主義的定義與本質，爭辯已久。而恐怖主義本質，無法藉由學術角度以較嚴謹方式加以定位，主要是因為恐怖主義、戰爭與組織犯罪，這三者的複雜關係無法加以仔細廓清。簡略言之，恐怖主義佔據人民的心理、戰爭佔據國家的土地，而組織犯罪則是追求私人的利益。此雖為簡要的區分，但仍可描繪這三者的基本差異。恐怖主義、戰爭與組織犯罪雖然在部分型態與模式有交集存在，但在目的與運作方式上有巨大的差異。本文主要目的在於釐清恐怖主義、戰爭與犯罪的複雜關係，探討其中的差異與相同之處，藉以凸顯恐怖主義的特質，最後檢討美國從小布希、歐巴馬到川普三屆政府對反恐行動的定位與影響。

The debate on the characteristics and essences of terrorism in academics has lasted for a long time. The main reason why “terrorism” cannot be defined precisely and rigorously is that the complex relations between terrorism, war and crime are not clearly explored. In short, terrorism occupies the human’s psyche, war occupies state’s territory and organized crime pursues personal profit. This distinction is short but essential. Although terrorism, war and organized crime share some common characteristics, they have major differences in the ways how they actually operate. This article attempts to explore the complex relations between terrorism, war and organized crime and discuss these similarities and differences. Finally the consequences of U.S. counter-terrorism measures will be reviewed.