Personally, I've always thought of the Dai Lee as being remarkably similar to the Praetorian Guard of Ancient Rome. The Praetorians, the elite legionaries, performed a very similar function in Rome to the Dai Lee's function in Ba Sing Se. The Dai Lee were founded by Avatar Kyoshi, and were initially there for the purpose of preserving Ba Sing Se's culture. Similarly, the Praetorians were originally founded by Emperor Augustus as a Police Force and Fire Brigade. Over time, however, the once benevolent organization grew ever more corrupt, and played a much more sinister role in the empire, toppling Emperors and replacing them with new ones, and playing a huge role in transforming the Prinicpate governament of the early Caesars into the military dictatorship of the late empire. Eventually, the Praetorian Guard became central to power politics in Rome. Whoever controlled the Praetorian Guard controlled Rome, and hence controlled the Empire. Several times throughout Roman history, new Emperors were able to rise to the throne simply by convincing the Prateorians that they were better off working for them, instead of whoever was Emperor at the time. This was inevitably followed with a swift coup in which the present emperor and his top generals were overthrown, and the new controller of the Praetorian Guard took control as the new ruler of the empire.

Sound familiar?