Some say that Bush went into Iraq because Saddam was going to change oil sales to Euros from the US $, and now look- Iran is next as they threaten to do the same. The battle was to save the "US Dollar Hegemony" and it is collapsing all around him. Without that, America cannot afford to police the world and be the imperialists they were before Bush.
Which part of the U.S. war machine is foreign? If I'm not mistaken, everything about their war machine is developed and built domestically. The U.S. is a huge exporter of arms, but they're hardly an importer of arms. The falling U.S. dollar, if anything, will make U.S. arms exports more lucrative.
If you haven't noticed, the U.S. Federal Reserve does not appear to be concerned with the fall of the dollar at all. I'm sure they recognize that it is not in anyone's best interest to allow the U.S. dollar to collapse. I'm sure they also figure that the falling U.S. dollar will help address the the growing trade deficit in some small but importantly meaningful way.
If the trade deficit slows, or even better, reverses, the U.S. economy will climb at an unprecedented pace. This will send investors running back to the U.S. markets and the U.S. dollar will once again rise to the occasion.
I'm no expert in economics, but I've come to recognize that economics can be looked at in terms of two metaphors: Dominos & See-Saws. That is, there are pretty much two principles that dominate economics. The first is that there are always consequences for everything. The second is that the consequences can be good or bad.
But like I said, I'm just learning this stuff. And I've still a very long, long way to go. So I could be wrong by a country mile -- or two.