Whether the Iraqi war matters in the "grand scheme of things" depends very much on your definition of "grand scheme of things".

I would argue that the war has already destroyed the US position as sole super-power. In global politics, the US president has been demoted to the biggest among equals, and the slide towards further loss of power is still ongoing.

The erosion of US power might not be too evident from inside the United States, but it is very evident here on the edges of the American sphere of influence.