In thinking about the ways in which Sept. 11 and our responses to it changed America and the world, it's important to remember that some of its impact, and perhaps the most historically significant aspects of that impact, may not have entirely emerged yet. In August 1945, for instance, while the advent of radar, jet technology and nuclear weapons were plainly evident, it would have been close to impossible to foresee the way in which the war effort, both domestically and in theater, would go on to inform the black civil rights movement and women's liberation movement 20-25 years later.
Beyond that, with regard to the most apparent changes to emerge over the past decade, the major impact of Sept. 11 was to accelerate the process of trends whose elements were already in place at the time of the attacks. Again, to use the example of World War II, the scientific trajectory that led to the use of radar, jet technology and atomic fission was already engaged. The war effort simply added an urgency that accelerated the technological advances as well as their application to warfare. The same thing is true for the post-Sept. 11 period regarding networked warfare -- which already accounted for the awesome display of American military power that overthrew Saddam Hussein's regime during the initial invasion -- and the proliferation in the use and application of drones and other robots. The technology and conceptual foundation were already there. The application was accelerated by the nature of the conflicts the U.S. chose to fight in the aftermath of Sept. 11.
I would also argue that the kind of overreach represented by the Bush administration's decision to invade Iraq was inevitable in a world where U.S. power had grown so disproportionately dominant. Any number of incidents and crises over the past decade might have been the trigger for a heightened U.S. response, including a military response, even by a presidential administration less dominated by neoconservative thought than the Bush administration. The Iranian, Libyan and Syrian nuclear programs all come to mind, as does the Russia-Georgia war and the various color revolutions that preceded it. That the U.S. handled these crises through diplomatic means had a lot to do with the fact that the U.S. military was already tied down in Iraq and Afghanistan. Absent those commitments, which were the result of miscalculation, it's not hard to imagine how we might have been drawn into other costly military adventures based on the same illusion of omnipotence and facility. In this case, I'm admittedly arguing a counterfactual, as Sept. 11 did in fact set in motion the process by which American hubris and global wariness of American power combined to shift the global order away from a unipolar structure and toward the emerging multipolar one. But human nature -- and the nature of power -- being what it is, I suspect that Sept. 11 simply accelerated a process that was inevitable.