The WTS position on working for the government has to do with what kind of work you do. For example the following are either forbidden, or restricted.
1) Military
2) Law enforcement/security which requires a gun to be carried
3) Neutrality in political areas such as the State Department, Congress, the President/VP office (for example)
4) Doing research on weapons
5) Being appointed politically rather than competing for the job through civil service
etc, etc, as you can imagine a Talmud of rules can apply.