For the American public, maybe, but not for those in power – things were already set in motion:

* The Afghanistan war was planned before 9/11 (see this and this)

* The decision to launch the Iraq war was made before 9/11. Indeed, former CIA director George Tenet said that the White House wanted to invade Iraq long before 9/11, and inserted “crap” in its justifications for invading Iraq. Former Treasury Secretary Paul O’Neill – who sat on the National Security Council – also says that Bush planned the Iraq war before9/11. And top British officials say that the U.S. discussed Iraq regime change one month after Bush took office

* Cheney apparently even made Iraqi’s oil fields a national security priority before 9/11

* The Patriot Act was planned before 9/11

* Cheney dreamed of giving the White House the powers of a monarch long before 9/11

* Cheney and Rumsfeld actively generated fake intelligence which exaggerated the threat from an enemy in order to justify huge amounts of military spending long before 9/11. And see this

* Cheney and the rest of the neocons lamented – before 9/11 – that America could not truly project its power globally without the justification of a “new Pearl Harbor”

* The government’s spying on Americans began before 9/11 (confirmed here and here. And see this)

* The decision to threaten to bomb Iran was made before 9/11

* The government knew that terrorists could use planes as weapons — and had even run its own drills of planes being used as weapons against the World Trade Center and other U.S. high-profile buildings, using REAL airplanes — all before 9/11

* The government heard the 9/11 plans from the hijackers’ own mouths before 9/11

* Cheney was in charge of all counter-terrorism programs for the United States before (and on) 9/11. See this Department of State announcement, this CNN article and this essay

* It was known long before 9/11 that torture doesn’t work to produce accurate intelligence, but is an effective way to terrorize people

via Did 9/11 Really “Change Everything”? → Washington’s Blog.