True enough MMC, let me tell you what I knew then. Between the time of the 9/11 attacks, and the invasion of Iraq, plenty of information was surfacing in news reports, in radio interviews as I listened to NPR daily as well as political talk shows.
In May of 2001 Afghanistan intercepts warn that Al Qaeda could attack American targets but the WH counterterrorism security group doesn't meet to discuss the prospect.
On June 9, 2001 Robert Wright, FBI agent wrote a memo to FBI headquarters complaining that the FBI's international terrorism unit is making no effort to neutralize known international terrorists living in the US.
I also found it beyond coincident that the two men who might have prevented the Patriot Act from coming to a vote, Tom Daschle and Patrick Leahy, both of whom had reservations about the bill, had their offices anthraxed. And subsequently claimed aboard the PA train!
Like the French, I wasn't convinced by Powell's speech before the UN.
I was amazed that Joe Wilson who was tasked with the job of determining whether or not Saddam Hussein had attempted to buy yellow cake from Niger. His report concluded that he had in fact made no attempt, though Bush claimed in his 2003 SOTU address that he had attempted the purchase.
I didn't believe that Saddam Hussein had the motivation let alone the means to produce a mushroom cloud over a US city and considered the claim hyperbolic.
I paid close attention to Hans Blix in interviews during his time in Iraq as he prepared preliminaries stating that Saddam Hussein was giving him unprecedented access, and after he was ordered out of the country prematurely, I read his scathing reports on Bush and Blair and his accusations that the policy to invade Iraq trumped the lack of evidence of WMD.
There were the disputed claims that Saddam Hussein was affiliated with AQ and OBL and so much more that just stunk like rotten fish to me and informed my position not to support the invasion which earned me ridicule by many friends and coworkers at the time, some of whom, that I still have contact with have accepted my opposition as correct in recent years.
All of which every democratic law maker was aware of and of course much more than I could have been aware of as well. So I personally don't accept the "if we knew then what we know now" argument.