Star Trek: 10 Starfleet Decisions With The Most Devastating Consequences

10. The Second Battle Of Chin'toka

The Dominion War was a brutal, drawn-out campaign that saw hundreds of millions of lives lost in the name of saving, or annexing, the Alpha Quadrant. While there were many individual battles in the course of the conflict, the Second Battle of Chin'toka was one of the most costly days in Starfleet's history.

While the Federation-Klingon-Romulan Alliance had seen several victories against the Dominion forces, they were ill-prepared to face off against the newest opponents - the Breen. While these secretive aliens had long been known to the Alpha Quadrant forces, the true extent of their technology had remained a mystery. That is until Captain Sisko led the task force that attempted to re-take the Chin'toka system - Starfleet's only foothold in Dominion territory.

Expecting a strong fleet to fight, the Allies were totally blindsided by the Breen's energy-dampening weapon. This directly led to the almost total destruction of their fleet, including the USS Defiant. Only a single Klingon Bird-of-Prey survived the encounter, which was left to accompany the hundreds of Federation escape pods, filled with demoralized troops, on the long trip back to their own territories.