The disgraced Cardassian officer Dukat forges an alliance between Cardassia and the Dominion, establishing a Dominion foothold in the Alpha Quadrant, in exchange for being made ruler of Cardassia. Realizing the danger, the Federation and Klingons join forces to slow the Dominion build-up, cooperating to plant a minefield across the entrance to the wormhole to prevent further invasion. Nevertheless, the Dominion begins to advance, and seizes control of Deep Space Nine. After a brief retreat, Sisko executes a successful return to the space station, but the wider conflict continues. More setbacks hinder the Alpha Quadrant alliance as additional races, such as the Breen, offer their support to the Dominion. Questionable tactics are adopted in the search for victory: Sisko uses manufactured intelligence and a murdered senator to convince the Romulans to ally with the Federation; and the Federation's covert-operations agency, Section 31, disseminates an engineered virus among the Founders. Dukat's successor as Cardassian leader, Damar, launches a successful resistance movement against the Dominion; in response, the Dominion attempts genocide against the entire Cardassian race. Eventually, the Dominion is forced back to the planet Cardassia Prime where it is cut off from reinforcements. The Changeling in command informs Odo, a renegade Changeling on the side of the Federation, that they will fight to the end to prevent any counter-attack by the alliance into the Gamma Quadrant. Odo assures her that the Federation would not do that while the other parties would be too weak to. Odo cures her of the disease afflicting her and the other Founders with the antidote he received, and the Dominion agrees to surrender.