In point of fact, a search of the Air Force Software Technology Support Center's much respected and widely circulated publication, "Crosstalk", with keywords like 'agile' and 'SCRUM', reveals well more than a hundred articles going back some years about projects across the DoD using agile methods in one form or another.
So where does this come from? Isn't the DoD the poster child for the BDUF--the big design up front?
Yes and no. For large mission critical weapons programs, yes. But DoD is not a monolith. In fact, the top-level guidance from the manual "Introduction to Defense Acquisition Management" as taught by the Defense Acquisition University has these words:
The primary objective of Defense acquisition is to acquire quality products that satisfy user needs with measurable improvements to mission capability and operational support, in a timely manner, and at a fair and reasonable price.
Not too shaby, and pretty agile when you think about it.
And, there's more: Consider what the very top level instruction to all DoD components says about doing things in evolutionary style, with rapid, incremental delivery [sound familiar?]
In point of fact, agile is an available method set for DoD programs. However, there are cautions: consider the points made in this presentation by Kristen Baldwin, then a senior DoD official in the software engineering and systems assurance office entitled "Agile in the DoD Environment" in 2006. On her page 17/20, she cites 'system of system' issues, scale, security, and a far-flung and somewhat independent customer base in the military departments as the main challenges. Any program manager that has worked on large scale programs can appreciate those challenges!
