NEG = New Earth Government.
There are really only two branches PCs are likely to run into (other than the all-pervasive military, that is):
The Federal Security Bureau (FSB) and the Office of Internal Security (OIS). Of the two, the FSB is widely considered to be the “good guys.” The FSB fills the role of the modern-day FBI, only with more power and authority. The old NSA was absorbed into the FSB when the US joined the NEG, as well, but the more … problematic … members of the NSA eventually jumped ship and moved to the OIS.
The OIS is like Homeland Security run amok, with a strong focus on Magic and other supernatural threats. They don’t have a leash and they’re not afraid to lock you up for as long as they feel is necessary. Also of note: Depending on the circumstances of your arrest, your civil rights may be (entirely legally) suspended.