If they would have been looking for a way to force the Partriot Act, they would have found another much more clever way than destroying two giant towers right in New York
I've seen videos of senators and white house staffers from the time saying that they'd had the patriot act on the shelf since the mid 90s but could never get it passed until after 9/11. Having trouble finding them now, but if you're interested I'm sure you'll find them.