It wasn't UNREASONABLE but I wouldn't say it was VERY reasonable. At the time a number of traditional US allies did refuse to (openly) participate in the "Coal

It wasn't UNREASONABLE but I wouldn't say it was VERY reasonable. At the time a number of traditional US allies did refuse to (openly) participate in the "Coalition of the willing". I think if you got your news from non-American and non-British sources at the time, I think there was far more uncertainty and doubt that Saddam had such weapons. I have heard this line before "Everybody at the time thought it" but I genuinely saw most people around me calling bullshit. There was a big sense of a grasping of straws from US intelligence, such as aluminium tubes being great evidence of nuclear development, and "we don't want the smoking gun to be a mushroom cloud". In fact it was remarkable just how much more bias the American media was then the global media at the time, and it doesn't seem to me like the American media had any special reason to be more confident that Saddam was nuclear than any of the media in the rest of the world. My theory wasn't that American mainstream media outlets like WaPo and NYT were going out of their way to start a war under false pretences, it was more that they had a lot of incentives to be bias in a pro-war direction.