The Cardassian Union showed all the signs of being a military police state, including a rigged judicial system and secret police. They had an effective intelligence network known as the Obsidian Order, but it was discredited when Founder spies tricked them and the Tal'Shiar into an ambush in the Gamma Quadrant.
Following the failed attempt to destroy the Founders on their homeworld, the Union came under attack from the Klingon Empire, which further depleted their military resources. In a desperate bid to retain power in the Alpha Quadrant, the remaining leaders of the Cardassian Union elected to ally with the Dominion.
In the aftermath of the Dominion War, the Cardassian Union has become a minor power that only controls a single, devastated planet.
Cardassians tend to be tall, with grey, scaly skin and pronounced ridges in their skulls, especially around their eyes. They are physically comparable to humans in most respects, although they have lower tolerance to cold. They are reputed to display pack-like behavior, desiring to establish -- or at least determine -- dominance in any social situation.
The Cardassian Union shares a border with the United Federation of Planets and lies within striking distance of the Klingon Empire. The actual extent of Cardassian territory at its height is not known, but it was probably similar to that of other major powers in the Alpha Quadrant.
The Cardassian Union was an expansionist regime that threatened any government near its borders, and it spent several years at war with the Federation before a peace agreement was reached. The Union invested heavily in military assets, but it remained slightly behind its rivals technologically. Despite their technological disadvantages, the Cardassian Union maintained sufficient fleet strength to remain a significant threat to the Federation.
In the aftermath of the Dominion War, the Cardassian Union controls little more than the Cardassian homeworld of Cardassia Prime and has minimal military assets remaining, effectively eliminating them as a major power in the Alpha Quadrant.
Cardassians of Note
- TNG "Chain of Command": This is not unusual behavior for social species, but presumably Captain Jellico perceives it to be more pronounced in Cardassians.