Looking back over 15 years later, it's easy to forget that a lot of people were skeptical of the CIA's findings that Saddam Hussein had active chemical and biological weapons programs. Of course, these findings were later found to be absolutely correct (though claims of Iraqi collaboration with Al-Qaeda turned out to have been greatly exaggerated).
But what if he didn't? How would it have affected the Iraq War and the War on Terror?
Well, it wouldn´t have affected the Iraq War itself much, Saddam only used them against Coalition forces when the situation started to look hopeless for him, as some kind of
wunderwaffen that could let him counter the clear superiority that the Coalition had then,and also to get enough casualties to break morale on the battlefield and at home, making the Coalition's victory so costly that public opinion would withdraw all support for the war and demand immediate peace, all while Saddam demonstrates to his subordinates that he is still the boss. Of course, by then, even with chemical and biological weapons, the US Shock and Awe tactics had already excluded any possibility of an Iraqi victory, and Saddam Hussein's strategy was seen as motivated by desperation and illusory thinking. In fact, the use of weapons justified the war retroactively and guaranteed its support even in places that once criticized it (for example: Chirac's France). Therefore, if there had not been any weapons to use in the first place, the war would have ended faster, with fewer casualties.
However, here matters a lot when it is discovered that weapons never existed. After all, it was the main justification for the intervention of the Coalition of the Willing, an intervention that did not have the support of the United Nations (which is perhaps difficult to remember now but was still considered relevant at that time) and therefore contradicted international law. If it had been discovered, this would have knocked down all of Bush's justification, and would have ended the political careers of those involved, since in the public opinion, it would have been showed that the anti-war movements were right about them, when they said that the leaders of the Coalition were warmongers who waged an illegal war because of lies and faulty data.
I, for example, can´t imagine Tony Blair still on the list of the best British prime ministers as it appeared in a survey that was made a few years ago, if that happened.
Therefore I imagine the following effects, at least:
*The left is going to be vindicated as the ones who were right, so they would be on the rise after the revelations (the reverse of what happened in reality).
*Neo-conservatism is going to receive a severe hit, with the isolationist wing being on the rise in the post-George W. Bush Republican party. Compassionate Conservatism is also doomed by association. The same for New Labour and its Third Way.
*The Doctrine of Building "Coalitions of the Willing" to decisively and unilaterally act (using military force) outside the UN system would be proved flawed, so the UN is going to recuperate part of the prestige it lost in the 90´s instead of being in a clear and fast decline.
*The War On Terror would have been less nightmarish in the Homefront, because the terrorists would not have easy access to chemical and biological weapons, like they did after the fall of the Iraqi regime OTL. Also, the great humanitarian crisis of 2003, caused by the after-effects of the biological weapons deployed in the war, that affected parts of Syria, Iraq and Kuwait, would not have happened.
