Not every conflict goes the way of Star Trek’s heroes—Pyrrhic victories, momentary defeats, escapes from scrapes that leave them bloody-nosed. But every once in a while we get to see, over the years, moments where the technological and strategic might of Starfleet is truly laid low: highlighting just how dire the stakes have gotten in Star Trek’s galaxy.
The Dominion War as depicted in Deep Space Nine will show up a lot here, because, well, it is pretty much the most devastating conflict in the history of the Federation as we know it—rivaled only, really, by the Federation-Klingon War touched upon in Discovery. And yet the first true shots fired in it still sting hardest, even if the casualty count is minor compared to other engagements.
The destruction of the USS Odyssey in the season two episode “The Jem’Hadar” sets the stage for just how bad conflict with the Dominion will go, a faction unlike anything the Federation has tried to engage with before—resulting in the shock moment a Jem’Hadar attack cruiser initiates a suicide run against the Odyssey, after the ship diverted power from its shield systems to weapons in an attempt to score any damage on the vessel at all. Metatextually, the fact the Odyssey was a Galaxy-Class ship—i.e., the same as TNG’s Enterprise-D—represented an even more dire warning to audiences: what was about to go down would be unlike anything Star Trek had ever seen.
The events facilitating the first season of Star Trek: Picard—publicly deemed a terrorist attack by rogue synthetic workers at the Utopia Planitia Fleet Yards, eventually revealed as a manipulation by agents of the Zhat Vash, a sub-branch of the Romulan intelligence agency, the Tal Shiar—resulted in a crisis so severe that it was in part responsible for Jean-Luc Picard’s resignation from Starfleet.
The impact of the attack was devastating, with over 90,000 people killed and the shipyards—Starfleet’s main production facility for ships—completely destroyed, as well as the atmosphere of Mars itself being set ablaze, rendering the planet inhospitable decades later. The attack led to the Federation outlawing synthetic life for nearly 15 years—and the destruction of the Fleet Yards, as well as the rescue flotilla being developed there, led to the Federation abandoning attempts to evacuate the Romulan homeworld, Romulus, before its impending destruction as the system’s star went supernova, resulting in the deaths of hundreds of millions more.
Although we never actually see it depicted on screen, only discussed, the surprise invasion of Betazed was one of Starfleet’s more embarrassing mishaps of the war. With the 10th Fleet assigned to protect the Betazoid homeworld and its colonies out of position on training exercises, a surprise assault by Dominion forces saw the planet fall to occupation in just 10 hours—giving the Dominion a foothold from which to strike at the heart of Federation space and putting the homeworlds of the Andorians, Vulcans, and Tellarites under threat of direct attack. The Federation attempted multiple times to reclaim Betazed, but it wouldn’t be until a year after its initial loss that the planet would be freed of Dominion rule.
The opening shot in the other infamous war in Federation history—its war with the Klingons in the mid 2250s—the Battle of the Binary Stars saw eight Federation vessels lost and thousands of Starfleet personnel killed and injured. At the time it was only the second major engagement Starfleet had had with the Klingons after a period of cold war and little interaction for both powers in the century prior, but it set the stage for a war that would claim the lives of 100 million Federation citizens.
Although not as bloody as other conflicts on this list—and arguably a tactical victory for Starfleet—the beginning of the Dominion War’s transition into a hot conflict saw Starfleet and its Klingon allies successfully complete a blockade of the Bajoran Wormhole, activating a minefield around Deep Space Nine that essentially cut off Dominion supply lines to the Gamma Quadrant. In distracting the Dominion and Cardassians at DS9, Starfleet also bought time to launch an assault a Cardassian-Dominion shipyard at Torros III, striking a crucial opening blow in the early days of the war.
But all that came at a heavy cost: Deep Space Nine was re-occupied by the Cardassians and their Dominion allies, with all Starfleet personnel forced to abandon the station during the invasion. It was a huge blow to the morale of the Bajoran people, who found the lingering threat of Cardassia on their doorstep once more just five years after the end of their homeworld’s occupation, even if Starfleet and its allies would eventually retake the station.
Touched on during Star Trek: Strange New Worlds, the moon of J’Gal—a disputed territory between Klingon and Federation space, and home to both Klingon and Federation colonies—played host to a horrific land battle between Starfleet and Klingon forces, largely a stalemate until the commander of the Klingon forces, General Dak’Rah, launched an indiscriminate assault on civilians, Klingon and Federation alike. Unable to contend with the slaughter, Starfleet withdrew from the world, having sustained nearly 210,000 casualties—but through machinations and a failed assassination attempt, Dak’Rah survived to defect to the Federation in an act of self-preservation, establishing himself as a prominent ambassador in the wake of the war.
The Breen’s surprise alliance with the Dominion during the war brought with it one of the most shocking moments of the conflict: a surprise bombardment on Earth itself. The Breen announced their entry into the conflict with a fleet bombarding Starfleet headquarters and San Francisco, and although defense platforms largely wiped out the invading Breen ships, Starfleet HQ and San Francisco took severe damage—inflicting a huge loss of morale among Federation civilians and Starfleet officers alike in this assault on the heart of the Federation itself, attacked directly for the first time in over two centuries.
The late stages of the Klingon-Federation War saw the Federation brought to the edge of total defeat when Klingon forces operating under House D’Ghor attacked Starbase 1—the very first orbital station of its kind established by Starfleet, and home to the bulk of its leadership. Some 80,000 people were killed in the invasion, including the vast majority of Starfleet’s Admiralty, setting the stage for a potential Klingon invasion of Earth itself.
The deadliest battle of the entire Dominion War was one of the most humbling in Starfleet history. No less than 311 of the 312 rallied ships attempting to hold onto the Chin’toka system—the Federation and its allies’ largest foothold into occupied Dominion territory—after the Dominion launched a new counterattack were destroyed during the engagement, due to the use of a surprise new weapon developed by the Breen Confederacy capable of completely disabling a starship’s systems and defenses, including the first USS Defiant.
Although the Dominion spared the escaping survivors as they fled their vessels in escape pods, the loss was so devastating to Starfleet that almost all military operations during the war were halted for a month, as engineers scrambled to counteract the threat of the Breen’s new weaponry.
Another rare entry on this list that is not from either the Dominion or Klingon Wars is still perhaps the most famous battle in Star Trek history: Starfleet’s engagement with Borg forces in the Wolf system, just eight light years from Earth. Compared to other conflicts mentioned here the numbers involved are much smaller in scope, 40 Starfleet vessels and a single Borg Cube. But Wolf 359 is devastating for the trauma it impacts on much of Star Trek itself in the years since its aftermath was first revealed in the iconic TNG two-parter “The Best of Both Worlds.”
Thirty-nine of the 40 Federation vessels at the battle were destroyed, including the Saratoga, the vessel where Commander Sisko served prior to his assignment to Deep Space Nine—and where his wife was killed during the battle. Wolf 359 was the engagement that saw Starfleet begin to develop the Defiant-Class cruiser, its first explicit warship designed in its history. And, of course, all the more devastating and most explored in the years since is the fact that all this carnage came at the hands of one of Starfleet’s most legendary heroes: Jean-Luc Picard, assimilated and transformed into Locutus of Borg, who would be haunted by his actions, even after his successful reclamation from the Borg, for decades after the fact.