The Patriot Act of 2001 destroyed checks and balances.

I opposed the Patriot Act because of the lack of checks and balances built into the legislation. Congress was being asked to give the executive enormous authority and then to step back and trust the executive to implement it responsibly.

The Patriot Act, to me, represented unchecked executive power. Congress was giving authorities to law enforcement that they had long requested, even before 9/11, and was agreeing to do so with minimal oversight built into the system.

I recommend to read all they have to say about it.

That said, the whole thing was already prepared and waiting in a drawer for something like 9/11 to happen. The USA was very much Not OK even before that.