I received a note last week from a former USAID administrator lamenting the fact that while the U.S. Department of Defense annual budget remains comfortably north of $700 billion, the U.S. Department of State struggles to keep its measly $58 billion per year. There are a lot of reasons why it's easier to pass a mammoth defense budget than to protect money reserved for foreign aid and diplomatic operations. If U.S. foreign service officers were constructed in as many congressional districts as the F-22, for example, I suspect we would have a lot more congressmen fighting to increase their ranks.
But in their excellent book Buying National Security: How America Plans and Pays for Its Global Role and Safety at Home, Gordon Adams and Cindy Williams offer another explanation:
The State Department's dominant culture -- the Foreign Service -- takes pride in [the department's] traditional role as the home of US diplomacy. Diplomats represent the United States overseas, negotiate with foreign countries, and report on events and developments. Diplomats, from this perspective, are not foreign assistance providers, program developers, or managers. As a result, State did not organize itself internally to plan, budget, manage, or implement the broader range of US global engagement ... State department culture focuses on diplomacy, not planning, program development and implementation.
They go on to lament that "Foreign Service Officers increasingly have responsibility for program planning, budgeting, and implementation, tasks for which they receive minimal training."
There are a number of ways in which military organizational culture changes, and the literature on the subject is extensive. (For an introduction, you can hardly do better than Theo Farrell and Terry Terriff's The Sources of Military Change: Culture, Politics, Technology.*) Strong leadership and emulation of other organizations are two ways in which change comes about, and external shock is another. The wars in Iraq and Afghanistan have, to a large degree, functioned as external shocks that have changed elements of the U.S. military's organization culture. I could be wrong, but I do not think those wars have had a similar effect on the Foreign Service.
*There is, of course, a much larger body of "rationalist" explanations for military change and innovation, starting with this book and this book. I am pretty well read in the corpus, but the best guy to explain the various explanations dispassionately is my buddy Mike, who is wicked smaht and who I am meeting for beers in about half an hour. (Yes, I know what time it is in the afternoon, but give me a break: I have just returned from Saudi freaking Arabia, and happy hour will begin this week when I want it to.)