As I discussed last week, the military does not like the idea of competing prototypes for weapons systems (Paid subscription required), and they are opposing this on the Joint Air-Ground Munition (JAGM) Contract.
They are claiming that it will cost an additional $1.5 billion dollars, but what it really comes down to is that it removes the opportunity to gold plate the system, and hence gold plate their retirement gigs, through changes in requirements after a winner is selected.