The Cardassian Rebellion, formally known as the Cardassian Liberation Front, was a popular uprising led by Legate Damar against the occupation of the Cardassian Union by the Dominion in late 2375. Although the revolt had little military impact and was quickly crushed by the Jem'Hadar, the uprising nonetheless had a great effect on the outcome of the Dominion War by forcing the Dominion to divert resources to quelling the rebellion, just as they were poised to launch a massive assault against the Federation, the Klingons, and the Romulans. Ultimately, the rebellion allowed the allies to win the war at the Battle of Cardassia, although their actions would have great consequences for Cardassia Prime.
By 2375, the Dominion's war effort against the allies was settling into a bloody stalemate. Damar, as leader of Cardassia, was becoming ever more frustrated with his Dominion allies, who had promised to return Cardassia to greatness but instead seemed intent on merely using Cardassia's resources to wage their war against the Federation and its allies. Initially, Damar tried to avoid his self-doubt by drinking excessive amounts of kanar and shirking many of his duties. (DS9: "Treachery, Faith, and the Great River")
Damar could not ignore Cardassia's problems, and after a meeting with Dukat, his predecessor as leader of Cardassia, he gained confidence, and resolved to win back Cardassia's standing in the galaxy. (DS9: "Penumbra") When it was revealed that the Dominion was negotiating with the Breen Confederacy, Damar was shocked to discover that Weyoun and the Female Changeling were planning to give away Cardassian territories in order to convince the Breen to join the war. Damar's anger only grew further when Weyoun callously sacrificed 500,000 soldiers of the Eleventh Order on Sarpedion V, supposedly to force the Klingons to commit more resources towards securing "a strategically worthless planet". (DS9: "Strange Bedfellows")
Finally, Damar could abide the treatment no further. He conspired with his friend, Gul Rusot, to launch a surprise attack against Rondac III, the Dominion's primary cloning facility. Together, Damar and Rusot recruited soldiers from the First, Third, and Ninth Orders and destroyed the Dominion's cloning facility. Although nearly half of Damar's troops were killed in the attack, the Cardassians were successful in launching a full-scale rebellion. As Damar announced the rebellion's success, he called upon Cardassians everywhere to resist: "Resist today. Resist tomorrow. Resist until the last Dominion soldier has been driven from our soil."
Damar's rebellion came at an incredibly opportune juncture, just as the Dominion was about to launch a massive assault against the Federation, the Klingons, and the Romulans with the Breen energy dampening weapon. Instead, the Dominion was forced to turn their energies inward to try to crush the rebellion, which gained the allies valuable time to try to find a countermeasure to the Breen weapon. (DS9: "The Changing Face of Evil")