Wars are cataclysmic events. Out of the destruction of major wars emerge new fault lines of international politics. To this extent, wars are the international, political equivalent of earthquakes, eruptions on the surface reflecting deeper underlying seismic shifts in the pattern of major-power relations.
The Cold War was unusual because of the longevity of the conflict and because of the peaceful manner in which it ended. The tectonic shifts ushered in by the realignment of forces after the Cold War were all the more significant, but they were hidden from view for an unusually long time because of the peaceful resolution.
It took the 9/11 terrorist attacks to force the pace of change and sharpen the new post-Cold War contours of international politics. This new shape is more visible after the Iraq war.