one thing I've wondered about... in OTL, of course, the US invaded Afghanistan and Iraq and embarked on a War of Terror around the world. Without 9/11, might the US's inclination towards isolationism kick in again, with an idea of 'forget about policing the rest of the world, let's fix problems at home." It's tempting to think about that huge amount of money spent on the WoT being spent at home instead...
Not if the Republican Party has anything to say. However organically things seemed to develop after 9/11 with regards to the public falling in behind the Neoconservative project for the Middle East, the gears were already moving towards that direction whether the people were on board for it. Now, could that strain of politics have gotten OTL levels of momentum and influence without 9/11? I'd actually say it's a toss-up.
The Rumsfeld's and Cheney's don't go away just because the world doesn't fall into their laps, they're scrappers and they'll fight for their wars at every opportunity. There will be more diplomatic incidents to exploit. Fox is always around to serve as their platform for shaping the national debate. They might not be able to take advantage of a national trauma for it ATL, but they have the tools to get those ideas out there. Remember, this is still post-Gulf War/ Grenada US. There is always a militarist strain in our politics and it's only tempered by keeping the memory of death and defeat fresh. That doesn't exist ATL, in either of the parties or the public.
The prospect of an air-war looks pretty likely even without a 9/11, and were there a sufficient excuse for it, Iran or Iraq could end up being invaded if the butterflies flap in the wrong direction. 9/11 was a VERY useful political moment, but it doesn't change much beyond the levels of support. And should the Republicans lose the midterms come 2002 that's still not an assurance of peace. Democrats watch Fox too.