One can build a very good predictive model of government agency behavior if one assumes the main purpose of the agency is to maximize its budget and staff count. Yes, many in the organization are there because they support the agency's public mission (e.g. protecting the environment at the EPA), but I can tell you from long experience that preservation of their staff and budget will almost always come ahead of their public mission if push comes to shove.
Despite being a Jerry Pournelle fan, I had never heard his Iron Law of Bureaucracy, but it certainly fits my observations
Iron Law of Bureaucracy
In any bureaucracy, the people devoted to the benefit of the bureaucracy itself always get in control and those dedicated to the goals the bureaucracy is supposed to accomplish have less and less influence, and sometimes are eliminated entirely.