|Art by Nico|
The civil servants of the Polity were it's most common face. Many were volunteers; others were drafted. They administered the noospheric fora (where members could petition the lords) and the Polity controlled hyperspace network, collected tolls, and handed out encryption keys for it's use to members. Through these measures the Polity effectively controlled interstellar trade and exerted soft power to shape planetary governments.
Not all it's power was soft. Polity membership made a sophont or a world subject to the justice of the Radiant Lords--justice meaning anything the lord in question felt would further the needs of the Polity and by extension humanity. They had a strict code and seldom acted rashly, as actions determined to be in error by review of their fellow lords carried harsh penalties, but they wielded great power and acted decisively--even brutally--when necessary. The lords all appeared baseline human, but their nervous systems were linked to their swift sophont ships, their brains modified with psybernetics (1), and their bodies enhanced. Each acted as a combination law enforcer, spy, advisor, and diplomat. When real war was needed, lords' code required they withdraw, and Hannibal Early was summoned.
In an effort to keep the peace, the Polity prohibited the export of irrational memeplexes such as religion between cultures. It was this prohibition that brought it into the conflict with the emerging Instrumentality of Aom and ultimately led to it's dissolution.
(1) It's believed that the psi-research NGO the Phaidros Group was involved with the Polity inception. If so, they abandoned it before it's final fall to begin their colony on Smaragdoz.