The Dominion Cold War is an unofficial term for the period from the Federation initial contact with the Dominion in late 2370 to the outbreak of the Dominion War in late 2373. During this time, the Alpha and Gamma Quadrant powers strived to establish strong diplomatic and military positions in preparation for the coming conflict.
For quite some time, the Dominion had been secretly collecting extensive information on the cultures of the Alpha Quadrant, but it was not until late 2370 that direct contact with the Dominion was established by Starfleet Commander Benjamin Sisko on a planet in the Gamma Quadrant when his team was detained by Dominion forces.
In response, Starfleet dispatched the Template:ShipClass USS Odyssey, with orders to investigate the Dominion threat and recover Sisko. Along with the runabouts USS Mekong and USS Orinoco, the Odyssey entered the Gamma Quadrant. The Starfleet force was intercepted and attacked by three Jem'Hadar attack ships.
These attack ships utilized phased polaron beam weapons that were completely unimpeded by the shields of the Starfleet vessels. Sisko and the Rio Grande were retrieved, but as the Federation vessels began to withdraw, a Jem'hadar attack ship made a suicide run, impacting the Odyssey and resulting in the total destruction of both ships. Sisko noted that the attack ship had made the suicidal attack not out of necessity, but to demonstrate "just how far they're willing to go."
Meanwhile, Dominion forces attacked and destroyed several vessels in the Gamma Quadrant, as well as the Bajoran colony on New Bajor. A Jem'hadar soldier, Third Talak'talan, arrived at Deep Space Nine to deliver news of the attacks, and a warning from the Dominion that the Alpha Quadrant powers were to "stay on your side of the galaxy".
Eris, a Vorta, had posed as another captive of the Dominion and accompanied the team's return to the Alpha Quadrant. Eris was exposed a Dominion spy when it was revealed that a collar that she had claimed restrained her telekinetic powers in fact had no capacity to do so. Upon being exposed, the operative was immediately beamed from the station, but not before warning Sisko, "You have no idea what has begun here."
Overtures for peace
After the destruction of the Odyssey, the USS Defiant, a Federation warship originally built to battle the Borg, was assigned to Deep Space 9 with orders to seek out the Founders and convince them that the Federation posed no threat. The Defiant was equipped with a cloaking device, loaned by the Romulan Star Empire for use exclusively on that ship and only when it was in the Gamma Quadrant, in support of the mission. In return, the Federation promised to share all intelligence gathered on the Dominion. (DS9: "The Search, Part I")
The Defiant located the Founders, a race of shape-shifters, though the attempt to make peace was unsuccessful. The Founders were a xenophobic culture driven by the belief that they could ensure their safety from solids only through universal conquest. Patient and far-sighted by nature, the Founders had begun establishing diplomatic and military inroads in the Alpha Quadrant in preparation for an invasion.
- See also: Battle of the Omarion Nebula
Over the course of several months, a fleet of Romulan and Cardassian warships were gathered in the Orias system. The fleet was small but formidable: its twenty ships were manned by combat veterans, and the Cardassian Template:ShipClass vessels had been upgraded with Romulan cloaking devices and more powerful engines. But when the fleet of twenty Romulan and Cardassian warships arrived at the Founders' homeworld in the Omarion Nebula, it found the planet deserted. Moments later, the fleet was ambushed by one hundred and fifty Dominion warships emerging from the nebula and was completely wiped out at what became known as the Battle of the Omarion Nebula. (DS9: "The Die is Cast")
The rout decimated the power of the Tal Shiar and Obsidian Order, previously identified by the Dominion as "ruthless and efficient organizations - a definite threat to us".
Intrigue and Manipulation
Shortly after the Omarion Nebula incident, the Dominion attempted to incite another war between the Tzenkethi and the Federation by using an autonomic systems parasite to seize control of the Defiant and compel the ship to attack the Tzenkethi. However, the parasite was neutralized before this plan could come to fruition. (DS9: "The Adversary")
In early 2372, due in part to the losses the Obsidian Order had suffered at the Battle of Omarion Nebula, the organization finally succumbed to the steadily growing power of the Cardassian dissident movement. The civilian Detapa Council overthrew the Central Command and, after 600 years of military rule, the Council became the effective governing authority of the Cardassian Union.
Believing that the Detapa Council could not have overthrown the military government on its own, the Klingon Empire claimed that its members had been replaced with changelings, and upon this pretext, launched an invasion of the Cardassian Union.
The Federation Council condemned the invasion. In response, the Klingon Empire withdrew from the Khitomer Accords, ending the peace treaty and alliance between the two powers. The formidable Klingon offensive overwhelmed the Cardassian forces. When Cardassia itself came under fire, Sisko rescued the Cardassian Detapa Council. Claiming the Council had been replaced by changelings, the Klingons demanded their surrender, launching a massive assault on Deep Space Nine. Skillful diplomacy backed up by incoming reinforcements enabled Sisko to convince the Klingons to withdraw, but Chancellor Gowron vowed to neither "forgive or forget" that the Federation had fired on Klingon forces. (DS9: "The Way of the Warrior")
Meanwhile, on Earth, paranoia gripped Starfleet Command. It was believed by some that the Founders had thoroughly infiltrated the Federation government - although the a Founder boasted that there were only three Founders infiltrating Earth. Acting on this intense paranoia, elements within Starfleet loyal to Admiral Leyton attempted a military coup d'etat in mid-2372, but the coup failed when the conspirators were exposed before the Federation Council. (DS9: "Paradise Lost")
In 2373, tensions between the Federation and Klingons erupted into war, over the issue of the Archanis sector, a dispute that had been outstanding for nearly a century. After learning from Deep Space 9 security chief Odo that Chancellor Gowron was possibly a Changeling infiltrator, Starfleet dispatched a team led by Captain Benjamin Sisko to expose the changeling.
As it turned out, it was not Gowron, but his trusted advisor General Martok, who had been replaced with a changeling, and that the impostor had used his position to influence Gowron to invade Cardassia and withdraw from the Khitomer Accords. After the impostor was killed, Gowron declared a cease-fire and agreed to renew peaceful negotiations with with the Federation, although occasional skirmishes continued until the Khitomer Accords were reinstated later that year. (DS9: "Apocalypse Rising", "Nor the Battle to the Strong", "By Inferno's Light")
Dominion fortification of Cardassian space, combined with the securing of non-aggression treaties with notable powers such as the Miradorn, Tholians, Bajorans, and most importantly the Romulans, had firmly established Dominion power in the Alpha Quadrant.
In mid-2373, the Dominion gained a physical foothold in the Alpha Quadrant by way of an alliance with Gul Dukat, who, leveraging the prestige he had gained through his rescue of the Detapa Council and courageous one-ship war against the Klingon Empire, assumed leadership of the Cardassian Union.
The Dominion began sending fleets of warships and supply vessels through the Bajoran wormhole to aid their new Cardassian allies. The Dominion supported a Cardassian offensive into the Demilitarized Zone, wiping out the Maquis, and forced the Klingons to withdraw from Cardassian space. In response, Chancellor Gowron renewed the Khitomer Accords, establishing the the Federation-Klingon alliance as the only remaining force capable of opposing the Dominion. (DS9: "By Inferno's Light")
With additional Dominion forces continuing to arrive through the wormhole, the Federation recognized the need to act. Unwilling to sanction a preemptive strike, the Federation decided to mine the entrance of the Bajoran wormhole, preventing further Dominion reinforcements from arriving.
The Dominion's pre-eminent representative, the Vorta Weyoun, arrived at Deep Space Nine to issue an ultimatum: if the Federation did not remove the mines, the Dominion would seize the station. When the ultimatum was refused, a Dominion/Cardassian fleet launched a "costly" offensive that nonetheless succeeded in capturing Deep Space Nine. Meanwhile, a Federation-Klingon alliance task force had destroyed the Dominion shipyards at Torros III.
The Dominion War had begun.