The US government has worked closely with a putative ally in a volatile, oil-producing corner of the world over the past few years.  That putative ally has received lots of military (and dual-use) hardware and knowhow to help it survive in a tough neighborhood, this help coming with a few strings attached and the tacit or overt support of the USG.  The putative ally, as with all such countries, has border issues with neighbors, some of whom are decidedly cool to the US and its relationship with the putative ally.  There's a history there, in other words.

At some point, the putative ally gets the idea that it can move forward with resolving, in a less-than-diplomatic manner, some of the issues with one of its neighbors.

The USG has been poking that ally's neighbor in the eye with a pointed stick for some time, leading to a decreasing level of friendliness in the US's relations with that neighbor.  More importantly, the US defense establishment sees the caboose on the gravy train coming around that bend over by the horizon.  Any military- industrial complex needs a steady source of contracts to make its incredibly expensive investments make sense, and the only sure steady source of contracts is trouble - not major, but simmering in a Cold War kind of way.  The major, go-to-serious-war kind of trouble is actually more dangerous to a military-industrial complex than it is worth.  In an existential conflict, by definition one can lose the war.  That's not especially appealing, particularly because losing means no more contracts.  Similarly, in existential conflicts, there tends to be actual oversight because people's sons are being drafted and they pay closer attention.  The military-industrial complex is not exceptionally worried, given that Cheney is in charge of the US defense establishment and it is stocked liberally with his proteges.  But there is some uncertainty, particularly about the future stream of contracts.

And, there's politics.  A Republican administration is looking at a defeat in the polls, given the economy is faltering and (shudder) tax increases may soon be needed.  The average guy is starting to wise up that the stock-market and financial industry profits of the last decade or so have come, not from increasing the productive ability of American business, nor from raised standards of living for Mr. and Mrs. Average such that they can buy more and