The U.S. government has been focusing on SOA for some time now, and in many instances has been successful -- perhaps more so than many in the commercial sector. However, the use of SOA approaches and technologies requires that you take into consideration what's unique about the government, including processes and governance requirements you won't find anywhere else.
The trouble with SOA and the government is that the government, even at the agency level, is huge and complex. Thus, the larger issue is how you get your arms around the problem domain and then move through a very slow procurement cycles to get the talent and the technology you require.
[ The feds have been early SOA adopters because they really need its advantages. ]
However, a clear pattern of success within the U.S. government when leveraging SOA is around the governance that typically exists within and between U.S. government agencies. This means that standards are typically defined, and there is a mandate to adhere to them. I find that while many of the standards are general in nature, it gets the agencies on the same page in terms of how to define their SOA and a standard set of requirements in terms of governance and security. Not perfect, but clearly productive.
Another pattern of success is the use of architects that have enough power to get things done, in a reasonable amount of time. They are active with the development of standards, and the use of those standards within the agencies they support -- generally speaking.
>However, there are patterns of failure. The talent thing is a huge issue within the U.S. government agencies looking to leverage SOA. This is a case where lowest bid perhaps won't serve you well in the longer term, considering the gravity of the strategy you're creating. Much of government IT is outsourced, and the talent and experience of the government contractor relates directly to the success of the SOA effort.
The great news is that the U.S. government is doing more right around SOA than wrong. They are looking at SOA as a strategy that will get their IT houses in order. As a taxpayer, I find that to be great news.