The Cardassian Union is less than a quarter the size of the Federation, and is located to the "west".

The Cardassians were once a peaceful, spiritual people, but Cardassia Prime was and is resource-poor, and starving citizens put the military into power. It began a program of conquest which continues to this day, and enjoys great popular support, since it brings in food, technology, and wealth.

Cardassia is a straightforward military dictatorship. It is governed by the Nine Military Orders. The Ninth, or "Obsidian Order", provides intelligence and espionage services. The Cardassian Union began a brutal but low-level conflict with the Federation in 2350. An uneasy truce was reached in 2366, and was more firmly established in 2367. In 2732 a civilian government was put in power; time will tell if it will outlast the recent Klingon/Cardassian hostilities. Cardassians behave like Klingons without honor and nobility, like Romulans without subtly and finesse. They freely use rape, torture, and mind control as instruments of policy. Most actions, even trade, cover war by other means. They lost a great deal when they lost Bajor and the Terek Nor space station, given the subsequent importance of the stable wormhole to the Gamma Quadrant, and there are not a few Cardassians who have been scheming to get all that back.