Captain Jean-Luc Picard's Enterprise-E was notably absent from the biggest conflict ever depicted in Star Trek: Deep Space Nine, where Captain Benjamin Sisko found himself on the front lines of the battle.
Despite the harrowing circumstances of the war, the USS Enterprise was never seen or mentioned engaging in the fight. The Sovereign class Enterprise-E was, at that time, the most advanced ship Starfleet had, notably repelling the Borg from an attack on Earth with relative ease a few years earlier in Star Trek: First . There's no concrete answer given within Star Trek lore as to why the Enterprise sat out the war, but there is a ing mention of Picard's vessel being used for diplomatic purposes during the war in Star Trek: Insurrection, and an obvious parallel is evident in Captain Christopher Pike's Enterprise not participating in the Klingon War a century earlier, held back by Starfleet as a last line of defense.
Where Was The Enterprise During DS9’s Dominion War
Only two adventures of the Enterprise-E during the era of the Dominion War were ever shown onscreen, as the cast of Star Trek: The Next Generation at that point had transitioned to making feature films. The first of these movies was Star Trek: First , which saw the Enterprise-E and an armada of Starfleet ships — including Star Trek: Deep Space Nine's Defiant, commanded by Lieutenant Commander Worf — defend Earth from the Borg before Picard and friends were forced to time travel to 2063 to prevent the Borg from stopping first between the Vulcans and a vulnerable post-World War III Earth. At that point the Dominion War was in the earliest stages, and likely wouldn't have required the Enterprise.
By the time of the next TNG movie, Star Trek: Insurrection, the war was ravaging much of the Alpha Quadrant, but the Enterprise found itself in a diplomatic role, strengthening existing alliances and fostering new into the Federation. Captain Picard was unhappy about this situation, but he reluctantly followed his orders. While the war's effects would linger for years, it was effectively over by the time of Star Trek: Nemesis, the final TNG film.
Why The Enterprise Wasn’t The Focal Point Of DS9’s Dominion War
There are practical and creative reasons why the Enterprise wasn't front and center during the Dominion War. By the late '90s when the story of the war was being told on Star Trek: Deep Space Nine, it would've been too expensive to have the likes of Patrick Stewart and Brent Spiner serve as recurring guest stars on the show, assuming the actors would have even been willing. Executive Producer Rick Berman was also not much of a fan of the Dominion War arc and likely would have vetoed any such guest appearances in an effort to keep the incredibly popular Star Trek: The Next Generation cast away from a story he didn't believe in.
From a creative standpoint, the Dominion War simply wasn't Picard's story. It was tailor-made for the cast of DS9, particularly Sisko, and any appearance by Picard and the Enterprise-E would have unfairly overshadowed them. That's not to say the aftermath of the war has escaped Picard completely. Showrunner Terry Matalas has suggested the galactic fallout from the Dominon War could factor into Star Trek: Picard's final season. The most consequential war in Star Trek history may have been fought without the Enterprise, but its seems as if its legacy will still have an effect on the ship's crew decades later.