Feel free to watch this interview with Bill Binney, who was technical director of the NSA at the time. He goes over it in detail. https://www.youtube.com/watch?v=3owk7vEEOvs
I am aware of ThinThread. The assertion made was "The Patriot Act was written and ready before 9/11". Do you have any specific pointers into where in this 2 hour 35 minute video that claim is made? Or better yet, does anyone have a pointer to anything in writing?
Yes. I believe that myopic, reactive legislators were able to go to the NSA/CIA/FBI and get lots of input on what they would like in a new bill. I am skeptical that "the Patriot Act was written and ready before 9/11".