I would like to see a poll that asks members of the U.S. public what they believe the purpose of the war is. My guess is that the #1 answer would be: "To free the Iraqi people from tyranny." It wouldn't surprise me if the #2 answer were something like: "To help Bush's friends in big oil."
Needless to say, neither of these is the right answer. But if Pres. Bush did a clearer job of explaining the rationale behind the war (the WMD threat), cogently and succinctly, without mixing it with secondary considerations, public support for the war would solidify. However, he is apparently still unwilling to do that in an unambiguous fashion.
Perhaps because if he did, the penny would drop, light bulbs would go off over peoples' heads, folks would be slapping their foreheads saying "D'oh," and so on and so forth.