The First Battle of Chin'toka was the first offensive launched by the Federation Alliance into territory held by the Dominion during the Dominion War. The battle, fought in late 2374, was a tactical and psychological victory for the allies, but failed to lead to a general invasion of Cardassian space. The heavy losses sustained in the battle forced the Allies to remain bottled up in the system so they were not able to advance any further, and as a result were easily contained by the Dominion. The system remained under almost constant attack until it was re-taken following the Dominion's alliance with the Breen.
Apart from the short and successful campaign to retake starbase Deep Space 9 during Operation Return about eight months previously, the Federation and Klingon Empire was fighting a wholly defensive war. Key planets, including Betazed, Coridan, and Benzar, had all fallen to the Jem'Hadar, while the Federation core worlds of Vulcan, Alpha Centauri, and Earth were coming into range of the Dominion war machine.
However, with the sudden entry of the Romulan Star Empire into the war, the allies had enough combined firepower to launch a full offensive on Dominion-held territory. Starfleet Command, in conjunction with the Klingon and Romulan high commands, agreed that the war could be won only by taking the war into enemy territory.