Without this external factor it's hard to find something to really feel the same about.
Would one of the states exiting the US be thinkable, were it not for the unity in waging wars against external (and some internal) enemies?
And yes. Leo Strauss was of that opinion and you will find a whole suite of argument that talk about how the middle east became the new enemy out of need rather than actual threat.
This was part of the PNAC (Project for New American Century) which identified the need for a new enemy after the fall of the wall.
Now whether they were actually successful is another discussion but it was part of the Bush administrations fundamental belief as several of it's key members where students under Strauss.