Perceptions of national security are changing--slowly. Earlier this month, the Washington Post reported that Pentagon officials were considering a major shift in strategy, one that, if adopted, would require significant changes in American force structure. The shift being contemplated is based on the view that traditional conceptions of national security have become outmoded since 9/11. (Of course, the fact that the 9/11 attacks were not thwarted might be taken as evidence that traditional conceptions of national security were outmoded before 9/11.) As the Post story puts its, "The plan's working assumption is that the United States faces almost no serious conventional threats from traditional, state-based militaries." Worrying about states is out; worrying about sub-state actors is in.
The report of the 9/11 Commission (on pages 361-62) explains the foundations of this shift in perspective:
In the post-9/11 world, threats are defined more by the fault lines within societies than by the territorial boundaries between them. From terrorism to global disease or environmental degradation, the challenges have become transnational rather than international. That is the defining quality of world politics in the twenty-first century.
National security used to be considered by studying foreign frontiers, weighing opposing groups of states, and measuring industrial might. To be dangerous, an enemy had to muster large armies. Threats emerged slowly, often visibly, as weapons were forged, armies conscripted, and units trained and moved into place. Because large states were more powerful, they also had more to lose. They could be deterred.
Now threats can emerge quickly. An organization like al Qaeda, headquartered in a country on the other side of the earth, in a region so poor that electricity or telephones were scarce, could nonetheless scheme to wield weapons of unprecedented destructive power in the largest cities of the United States.