The first cases turned up ten miles down the road from where Atta and other 9-11 jackers were staying, and there is no other reasonable source for such stuff those guys would have had other than Saddam Hussein.
There are lots of sources now that it's official that the anthrax was not "weaponized". It was merely well grown, cleaned and ground.
The letters were postmarked a week after 9/11, and the location where the hijackers trained was already reported in the news by then - the National Enquirer letter seems to me an attempt to create a false geographic link to the hijackers.
There's so much people just dance around or ignore - like why Daschle and Leahy, of all people, are the governmnental figures singled out for animus by Al Queda or Iraq, in the second set of attacks.
I disagree with the "no other reasonable source" part. There are literally tens of other possible sources, if you count governments and agencies within governments separately.