Why is the US gov on the internet in the first place? It's a work enviroment so they should have zero internet access bar one standalone PC and a locally attached printer. If someone needs a webpage, fill in the request form (in triplicate), someone in a haz-mat suit (so they don't get infected with any viruses) enters the URL and prints the page in triplicate. One goes to the requestor, one goes to their boss and one goes to the NSA.
SImple.