Eve Fairbanks has done an excellent comparison of American and Israeli politics during and after wars that have not gone well.
I have to quibble with her on one detail. We found WMD, to the tune of at least 500 shells with sarin and mustard gas. Before anyone complains about the age, keep in mind that World War I chemical weapons have caused injuries in France and Belgium.
That quibble aside, Eve has a good point. It would be nice to see politicians admit that they have screwed up, or that they don't have any alternative solutions. Or to admit that things have not gone as well as hoped. That said, humility is a critically endangered species once one gets inside the Beltway. Not only that, but there is the fact that those who do show any - or who try to be open - often get torn apart by people who look for the slightets hint of weakness. The DC press corps tends to act like a bunch of piranha at that point. See Rumsfeld's explanation of going to war with the army you have, not the army you wish you had as a classic case.
I guess I'm becoming a bit of a cynic about that sort of thing.