I remember reading about this a while ago. I don't have the links to the articles on the device I am using however they mentioned three things:
1). The organisation would need the skills and resources to bake in back doors (e.g. knowledgeable people).
2). Free speech - Can you make a programmer code (speak) something they do not want to say.
3). Assuming someone is willing to help - it may take one person years to do as they have been asked, so during that time are they employed by the government? Do they get assistance (e.g. mentoring or hardware) to do the task?
As you can see it would be difficult to implement I think.
Thanks