Dominion cold war The Dominion cold war was a period of events between the initial official first contact between the United Federation of Planets and the Dominion in late 2370 , to the onset of the Dominion War three years later . The cold war was largely defined by repeated Dominion infiltration of various Alpha Quadrant powers , intending to unravel the political alliances that had largely kept the quadrant in peace . Several of these infiltrations were highly successful , triggering conflicts between major powers . Prelude . In 2369 , the Federation discovered the Bajoran wormhole in the Denorios Belt . Almost immediately thereafter , ships from various powers of the Alpha Quadrant began exploring and colonizing the Gamma Quadrant . The first Alpha Quadrant species to gain knowledge of the Dominion were the Ferengi in 2370 , when they negotiated a trade agreement with the Karemma , an important mercantile member of the Dominion . ( ) Further reports of the Dominion continued to trickle through to the Alpha Quadrant : the Skrreea related that their former oppressors , the T - Rogoran s had recently been conquered by the Dominion . Also , a Yaderan named Rurigan informed Deep Space 9 personnel that his homeworld Yadera Prime had been conquered around 2340 . ( ) Contact . During the Alpha Quadrant ' s colonization of the Gamma Quadrant , the Dominion had been collecting extensive intelligence on the major powers on the other side of the wormhole , but remained elusive . In late 2370 , official first contact was made when Commander Benjamin Sisko and Quark had been detained by the Jem ' Hadar , alongside a Vorta , Eris , who claimed to be a refugee from the Dominion conquest of Kurill Prime . The Jem ' Hadar had followed this up by destroying a number of ships and colonies in the Gamma Quadrant , including New Bajor colony . This news was delivered to Deep Space 9 by Third Talak ' talan , along with the overt threat that the Dominion would no longer tolerate Alpha Quadrant encroachments into Dominion territory , which was perceived to be anything on the Gamma Quadrant terminus of the wormhole . In response , Starfleet dispatched the , supported by the runabout s and , both as a show of force and to recover Benjamin Sisko and the runabout . Although Sisko and his expedition were successfully retrieved aboard the " Rio Grande " , the Starfleet force had been intercepted by three Jem ' Hadar attack ships . The former rapidly found themselves to be hopelessly outmatched by Dominion firepower , as it was capable of penetrating Starfleet deflector shield s with phased polaron beam s . After retrieving Sisko , Starfleet attempted to withdraw . In a demonstration of Dominion resolve , one Jem ' Hadar fighter rammed the " Odyssey " s main deflector in a kamikaze run , destroying it with all hands . The remnants of the Starfleet force were permitted to withdraw . Back on Deep Space 9 , Eris had been exposed by Quark as a Dominion agent , further revealing that the Jem ' Hadar offensive was a ruse to plant her in Federation territory . Eris promptly beamed away , leaving the crew of the station with a warning : " " You have no idea what ' s begun here " " . ( ) Escalation . After the destruction of the " Odyssey " , Starfleet assigned the , a prototype warship originally built to combat the Borg , to Deep Space 9 . The Federation hoped to avoid all - out war , and so ordered Benjamin Sisko to take the " Defiant " into the Gamma Quadrant to seek out the Founder s and convince them the Alpha Quadrant posed no threat . ( ) After establishing contact with the Karemma , the " Defiant " was ambushed and captured by a Jem ' Hadar squadron . The crew was detained on the in the Omarion Nebula , where they were subjected to an elaborate simulation by Borath , intending to ascertain how the Alpha Quadrant powers would react to an overt attempt by the Dominion to establish an influential foothold in the Alpha Quadrant . The Dominion concluded they would be met by strong resistance and suspicion , with some preferring the destruction of the wormhole rather than accept Dominion influence . The " Defiant " was subsequently permitted to return to the Federation , though only through Odo ' s intervention . ( ) Following these events , the Dominion threat seemed to recede , although the Federation and neighboring powers still regarded a Dominion invasion as only a matter of time , and began preparations . Deep Space 9 was heavily fortified , and , in mid - 2371 , a relay station and a series of listening post s were established on the far side of the wormhole to provide advance warning of a Dominion incursion . ( ) Despite the constant Dominion threat , exploration and trade through the wormhole resumed . This exploration was not without its danger , however , as several Starfleet vessels went missing , presumed destroyed , in the Gamma Quadrant : the , the , and the . ( ) Initial infiltration . Dominion quiescence , however , was deceptive . Multiple Changeling agents were situating themselves at the highest environs of power in the Alpha Quadrant ' s powers . Though Starfleet and the Klingon Defense Force s were implementing sweeping security measures to combat Changeling infiltration , these measures proved to be ultimately ineffective , and were easily countered by the Changelings . ( ) The Dominion soon prioritized the Romulan Tal Shiar and the Cardassian Obsidian Order as key targets to be eliminated . The Dominion learned of a plan concocted by Enabran Tain , former head of the Obsidian Order , to form a strategic alliance with the Tal Shiar , with the ultimate goal to cripple the Dominion by wiping out the Founders . A Changeling assumed the identity of Romulan Colonel Lovok as a guarantee that Tain ' s plan would be carried forward . In 2371 , a secretly assembled fleet of Tal Shiar and Obsidian Order warships bombarded the Founders ' homeworld , only to discover it was a trap . A large fleet of 150 Jem ' Hadar fighters ambushed and destroyed the fleet , crippling the Tal Shiar and eliminating the Obsidian Order altogether . ( ) Shortly after the incident at the Omarion Nebula , masquerading as Federation Ambassador Krajensky attempted to incite war between the Federation and the Tzenkethi . The Changeling sanctioned a mission based on false rumors the Tzenkethi were preparing aggressive moves toward Federation border colonies , and ordered the " Defiant " to present a show of force . While en route , the Changeling hijacked the ship , and attempted to use it to attack the Tzenkethi settlement on M ' kemas III . The " Defiant " crew were able to neutralize the Changeling in time to avert war . ( ) The Alpha Quadrant destabilizes . The fall of the Obsidian Order following the had left a power vacuum on Cardassia . The Cardassian Dissident Movement had taken advantage of the situation and managed to successfully topple the Cardassian Central Command in early 2372 , restoring the authority of the civilian Detapa Council . Some time prior to this , had infiltrated the Klingon Empire and assumed the identity of General Martok . Using this position , the Changeling convinced Chancellor Gowron that the Cardassian revolution could not have succeeded without Dominion involvement , and proposed a preemptive strike against the Cardassian Union to ensure the security of the empire . The Federation Council publicly condemned the invasion and refused to commit support , compelling Gowron to withdraw from the Khitomer Accords , shattering the Federation - Klingon Alliance . Captain Benjamin Sisko managed to preserve the Cardassian state ' s leadership by sheltering the Detapa Council on Deep Space 9 , and withstanding the subsequent Klingon assault . ( ) Despite pleas from Sisko that interstellar conflict was exactly what the Founders desired , Gowron ordered his forces to fortify their conquests in Cardassian territory , effectively continuing the Klingon - Cardassian War , arguably the most successful result of Dominion political machinations in the Alpha Quadrant . The war soon degenerated into a war of attrition , resulting in heavy casualties , devastating the Cardassian Union . Meanwhile , on Earth , a Changeling infiltrator detonated a bomb at the Antwerp Conference in mid - 2372 , shattering some two centuries of peace . Admiral Leyton , long convinced that Federation President Jaresh - Inyo was ill - prepared to face the Dominion threat , attempted a military " coup d ' etat " with a cadre of loyal Starfleet officers and the unwitting collusion of Starfleet Academy ' s Red Squad . The " coup " was ultimately unsuccessful after the " Defiant " reached Earth with evidence of Leyton ' s conspiracy , averting a potential Federation civil war . ( ) The Martok Changeling proceeded to manipulate Gowron into laying a revanchist claim to the Federation Archanis sector in late 2372 . Following the Federation ' s refusal to leave Archanis , the began . A Starfleet infiltration team exposed Martok as a Changeling and secured a ceasefire with the Klingon s in early 2373 , though tensions remained high including a Klingon attack on Ajilon Prime . ( ) By mid - 2373 , the Klingon - Cardassian War had taken its toll . The infrastructure of the Cardassian Union had been severely weakened as Klingon ships marauded through their territory . The Maquis under Michael Eddington had taken the opportunity to informally ally with the Klingons ; they all but drove the Cardassians out of the Demilitarized Zone and were preparing to declare themselves an independent state . The Dominion was later indirectly aided when a Borg incursion inflicted severe damage upon Starfleet ' s military capabilities . ( ; ) Shamed and humiliated by the repeated Cardassian defeats , Gul Dukat began conducting secret negotiations on behalf of the Cardassian Union to join the Dominion . Dominion foothold . Sapped by two years of conflict , Starfleet determined its depleted strength would be unable to resist a Dominion attack . In mid - 2373 , a large Dominion fleet was discovered hiding in a nebula in close proximity to the Bajoran wormhole . Starfleet enacted a contingency plan to permanently seal the wormhole using a phase - conjugate graviton beam . However , Deep Space 9 had been infiltrated a month earlier by a posing as Doctor Julian Bashir . This Changeling sabotaged the beam to strengthen the wormhole instead , rendering it invulnerable to any form of explosives . ( ) With their lifeline to the Gamma Quadrant secured , the Dominion invaded the Alpha Quadrant . However , rather than attacking Deep Space 9 and securing strategic control over passage through the wormhole , the first wave of Jem ' Hadar warships set course for Cardassia . Gul Dukat publicly announced the Cardassian - Dominion alliance , with himself as its leader . The alliance was generally embraced by the Cardassian people , and Dukat made a public plea promising to restore Cardassian pride . He made good on his promise ; in just three days , the Jem ' Hadar forced the Klingons into full retreat and massacred the Maquis in the Demilitarized Zone . ( ) Believing a Dominion attack to be imminent , Benjamin Sisko convinced Gowron to reinstate the Khitomer Accords . Starfleet and Klingon forces prepared to make a united stand at Deep Space 9 , surprisingly joined by Romulan forces . Rather than launch a frontal offensive , the Bashir Changeling attempted to induce the Bajoran sun to supernova with a protomatter - trilithium bomb , potentially wiping out the station and the combined fleet . The " Defiant " successfully prevented the Changeling from succeeding . ( ) Although open war did not begin immediately , violence along the Federation - Cardassian border escalated , with ships such as the Starfleet vessel and the Klingon warship being reported missing . Tensions with the Dominion rapidly grew over the following months . The Dominion began sending large weekly convoys of warships , troops and supplies to fortify the Cardassian Union . The Dominion also began undermining potential alliances to isolate the Federation and the Klingons ; they signed nonaggression pact s with the Miradorn , the Tholian Assembly , the Bajoran Provisional Government and , most significantly , the Romulan Star Empire . ( ) Open war . For the Federation - Klingon Alliance , the strategic situation was severely deteriorating . With war considered inevitable , Starfleet resolved to permanently halt the Dominion convoys by mining the entrance to the wormhole with self - replicating mine s , an act which was considered provocative enough to trigger open war . Indeed , Weyoun arrived on Deep Space 9 to deliver an ultimatum ; either Sisko removed the mines , or the Dominion would . Despite subsequent posturing , in which Weyoun agreed the Dominion could limit the convoys to medical and economic assistance , both sides knew that it was only a matter of time before war began . Only two days later , a large Dominion - Cardassian fleet launched a successful , if costly , attack on Deep Space 9 , though not before the minefield was activated . The diversion of Dominion ships allowed a Federation - Klingon task force to cross into Cardassian space and destroyed a Dominion shipyard at Torros III , dealing them an early strategic blow . The Dominion War had begun . ( )