The US is more susceptible to terrorism largely because of its rhetoric. They could for example, get drawn into or prolong a war. But that's not the same kind of threat that even dwarfs like N. Korea or Iran present. Terrorism fast hits a brick wall. If attacks become common in The States (eg 5 per year) long term, they will get used to it. Just like gang violence. You could theoretically just ignore it & the US would still be the US. The same could not ba said of the Cold War War II, or any other 'real' war.