It isn't a question of how this tricky little intellegence SNAFU happened (although it's an interesting side-light). If Americans and the world had been told the truth from the beginning then there likely would not have been a war.

Now that the thing is accomplished, it's fine for you true believers to assert "Going to war to abort Husseinism is justified.". But if you take away the various "credible proof"s of NBC warfare capabilities [better Fox?] and of terrorist links, a lot of the folks who supported the war, would not have done so. And they have every right to be righteously pissed.