Second Battle of Deep Space 9 The Second Battle of Deep Space 9 was the opening engagement of the Dominion War , in which the combined forces of the Jem ' Hadar and the Cardassian Union , under the nominal command of Gul Dukat , captured Federation starbase Deep Space 9 . Fought in 2373 , the Dominion launched the assault to prevent the mining of the Bajoran wormhole , which would effectively sever supply lines from the Gamma Quadrant . Two days after Captain Benjamin Sisko rejected Weyoun ' s ultimatum to remove the minefield , a large fleet of Jem ' Hadar and Cardassian warships launched an assault on the station , intending to capture it before the could complete the minefield . Although the Dominion successfully captured the station from the Federation and drove Allied forces from Bajoran space , the losses they incurred were severe ; fifty ships were destroyed in the battle , and the Dominion was unable to prevent the activation of the minefield . Prelude . Following their annexation of the Cardassian Union around stardate 50560 , the Dominion began fortifying their foothold in the Alpha Quadrant with weekly convoy s of warships and troops through the wormhole . As time went on , Cardassian space became a veritable fortress , teeming with Jem ' Hadar soldiers and their Vorta overseers . ( ) Although a technical state of war did not exist , and neither side had fully committed to immediate combat , numerous skirmishes took place along the border during this period . Aside from the Dominion ' s attempt to destroy the Bajoran system using a trilithium bomb , the Jem ' Hadar and the Cardassians attacked and destroyed numerous Federation and Klingon patrol ships in a sustained campaign across the border sectors . Casualties of these attacks included the and the . ( ) In addition to the military advances , the Dominion made major inroads into the Alpha Quadrant politically as well , signing nonaggression pact s with several regional powers , including the Miradorn and the Tholian Assembly , and offering similar pacts to Bajor and other independent worlds in the area . The Dominion ' s greatest diplomatic achievement , however , was the signing of a nonaggression pact with the Romulan Star Empire , the third major power in the region . The Dominion ' s goal seemed clear : to isolate the Federation politically and militarily . Its classic strategy of divide - and - conquer seemed to be succeeding admirably . Only the Klingon Empire stood with the Federation against the Dominion . With peaceful means failing to slow the Dominion ' s advance , Benjamin Sisko observed , " " . . . a war may be our only hope . " " ( ) Provocation . With its strategic position rapidly deteriorating , the Federation resolved to prevent the Dominion from sending further reinforcements into the Alpha Quadrant by mining the entrance to the Bajoran wormhole . Maintenance engineer Rom suggested using self - replicating mine s equipped with cloaking device s for the blockade ; not only would such a minefield be undetectable to approaching ships , but it would also be virtually indestructible , as each mine destroyed would be replaced by another mine in the vicinity . Chief Miles O ' Brien and Lieutenant Commander Jadzia Dax quickly developed a working model , and the " Defiant " began laying down the minefield . This action could be seen as nothing less than a major provocation however , and the Dominion ' s primary representative Weyoun promptly demanded that the mining of the wormhole be halted immediately . Captain Sisko flatly refused . An intricate dance of lies and intimations began : Weyoun claimed that the Cardassians , having suffered terrible damage during the Klingon - Cardassian War , required massive assistance in rebuilding their infrastructure and defenses following the Klingon invasion . Sisko played along , claiming to have had no idea of the Cardassians ' dire humanitarian situation . The two representatives arranged a deal , in which the Federation would remove the minefield , and the Dominion would restrict further convoys to nonmilitary personnel and materials . However , both sides recognized this repartee as nothing more than a ruse to buy time – Weyoun to prepare the Dominion fleet for the attack , and Sisko to complete the minefield . With war imminent , Sisko , speaking both as a Starfleet captain and the Emissary of the Prophets , advised that the Bajoran government sign the nonaggression pact offered to them by the Dominion , thus ensuring that the planet and its people were kept out of the now - inevitable conflict . The pact was passed , and First Minister Shakaar Edon ordered the evacuation of all Bajoran personnel from the station . ( ) The Battle . Intent on preventing its lifeline to the Gamma Quadrant from being blocked , the Dominion launched a massive assault fleet towards Deep Space 9 , with Gul Dukat himself in command . For reasons not yet publically known , the Federation had not reinforced its position at Deep Space 9 , leaving only the USS " Defiant " and the to supplement the station ' s defenses . Anticipating the enemy attack , Sisko ordered the " Rotarran " to patrol the border and provide advance warning when the Dominion fleet approached . Captain Sisko confidently rejected Dukat ' s offer to surrender , and both sides prepared for the onslaught . Dukat ordered five Jem ' Hadar attack wings to intercept the " Defiant " , while his remaining ships targeted the station . As the Dominion fleet opened fire , Weyoun and Dukat were unpleasantly surprised to find Deep Space 9 ' s shields holding up under the barrage – Federation deflector shields had previously been impotent in defending against the Jem ' Hadar ' s phased polaron beam weaponry . Dukat ordered more ships to open fire on the station . Meanwhile , the " Defiant " herself was coming under fire as she was laying the minefield . The " Rotarran " provided interference and covering fire , giving the " Defiant " enough time to complete and activate the minefield , sealing off the wormhole . Using his knowledge as the station ' s former commanding officer , Dukat was able to cut main power to Deep Space 9 ' s shields by directing all Dominion firepower into section 17 of the outer docking ring . With the wormhole now blocked , and the station becoming an impossible position to hold , Captain Sisko ordered all Starfleet personnel to evacuate Deep Space 9 . As Dukat ordered his reserve units to enter the battle , the station ' s Starfleet crew boarded the " Defiant " and the " Rotarran " , taking all sensitive equipment with them and leaving the station in the hands of the Bajoran Militia . As the evacuation neared completion , Sisko addressed the remaining station residents on the Promenade , promising , " " I will not rest until I stand with you again , here , in this place where I belong . " " Once the " Defiant " and the " Rotarran " had safely departed the station , Major Kira Nerys , now the Bajorans ' representative to the Dominion , activated Program Sisko 197 . The program completely sabotage d the station ' s computer and power systems , leaving the station a nearly lifeless hulk . The Dominion and Cardassian troops boarded the station without resistance , officially reclaiming Terok Nor , the station they had abandoned in orbit of Bajor five years before . ( ) Aftermath . Dukat and the Dominion captured Deep Space 9 from the Federation , but the more than fifty Dominion ships destroyed were a major price to be paid for that victory . The minefield operated independently from the station and proved resistant to all initial attempts to dismantle it . Likewise , the sabotage of the station itself meant that in the short term it would serve little function other than as a command and supply outpost behind the front lines . In addition , while the Dominion had thrown its full force towards capturing the station , a combined Starfleet - Klingon task force had crossed the border into Cardassian territory and destroyed the shipyard s at Torros III , which in the eyes of Starfleet Command outweighed the loss of DS9 . ( )