Flag Territory In the mirror universe, the Klingon-Cardassian Alliance was a coalition government formed by the Klingon Empire and the Cardassian Union in 2295 as a counter to the Terran Republic, the short-lived successor state of the Terran Empire, as neither power alone possessed the strength of arms to defeat the Imperial Starfleet. The key to such an alliance between these two nations was the Republic of Bajor, whose role as a power-broker ensured a level of equality that otherwise would not have been able to exist. The Alliance defeated and conquered the Terran Empire, already weakened by the reforms of Terran Emperor Spock, and condemned all non-Alliance races and cultures to slavery. (DS9 episode: "Crossover")