I'm sure geography, neutrality, defenses, and the banks were all important factors for preserving peace.

I think the main point of contention about the effectiveness of neutrality to prevent things like terrorism is whether the Islamic extremists attack us because we intervene in their affairs, or if they attack us because they want to destroy freedom and our way of life, as Bush puts it. I'm sure a couple of them simply want to destroy us, but I'm sure Bin Laden would find his recruit pools rather dry if not for America's arrogant and interventionistic foreign policy.