Over at the Tor.com review of Star Trek: Deep Space Nine's third season episode "The Die Is Cast", author (and notorious SJW†) Christopher L. Bennett expresses some uncertainty over how the show later depicted the aftermath:
I have a hard time believing this battle would wipe out the entire Obsidian Order and Tal Shiar. I mean, those are both intelligence agencies/secret police. They’d be mostly ground-based bureaucracies staffed mainly by people in desk jobs working out of offices. Are we supposed to believe that these battle fleets were crewed by the entire administrative and office staffs of those agencies as well as every one of their operatives? Would any devious, secretive, manipulative intelligence agency be so reckless as to send all its key personnel on a military mission, rather than maneuvering someone else into taking the risk for them?Unless the idea is that the defeat was such a debacle that it led to both agencies’ entire staffs being purged or executed. That I could buy. And in the case of the Obsidian Order, which we know was locked in an ongoing power struggle with Central Command and the Detapa Council (so it was actually technically 1/3 of the government, though in practice it and the CC had all the actual power), I can buy that its rivals would’ve taken the opportunity to dismantle it once and for all. But in the case of the Tal Shiar, it seems more likely that it would just be restaffed rather than dissolved.
Understand that I don't have anything to contrast this with than head canon, but in fairness neither does Bennett. However based on what has been established on screen (and ignoring things also established on screen that contradict the things established on screen I'm about to talk about, as all Trek head canon inevitably must do) I can explain away what I think happened.
† Yes, this is the same Christopher Bennett who complained that a male character in an 11th century Japanese novel wasn't an ardent feminist.
First let's go over what we can all agree on, more or less:
- The Romulan Star Empire lost a number of warbirds: Memory Alpha says 5 of the 20 ships were Romulan
- Several Cardassian ships were destroyed: Memory Alpha says 15 (since that's 20-5)
- Numerous Tal Shiar and Obsidian Order operatives were killed, including Inabarin Tain.
Strangely, that's about the entire list, and even then the numbers are in dispute. Toddman says there are 20 ships but the breakdown is only conjecture (based on the 15 ships leaving the Orias System in the third season DS9 episode "Defiant"). From a numerical perspective alone that should placate much of Bennett's opposition: presuming similar staffing levels (which is probably unfair, since the D'Deridex-class warbird is 1341m long, versus the 481m long Keldon-class Cardassian battlecruiser) the Cardassians lost three times as many people.
However the important thing to remember is how the Cardassian and Romulan governments integrate their military with their secret police. In "Defiant", Dukat explained to Sisko that the Central Command and the Obsidian Order both (in theory at least) reported to the civilian Depata Council, and in practice operated in a "silo" where they generally conducted their own affairs. However, and this point was critical: the Obsidian Order was not permitted to own military equipment.
By contrast our major example of how the Tal Shiar integrated with the Romulan military comes from their first appearance in the Star Trek: The Next Generation episode "The Face of the Enemy" where Troi goes undercover as a Tal Shiar operative. However the dynamic in that episode is in stark contrast to how the Obsidian Order operates: in "Defiant" the OO only had Korinas as an observer, and the only "orders" she gave was instructing Cardassian techs to lock down their workstations. In "The Face of the Enemy", Major Rakal (as Troi is pretending to be) is able to order the captain not to look at cargo, to travel to specific locations, and it's understood to be part of her normal capacity. Troi does eventually take command of the ship, but it's clear that she's simply overstepping her technical authority by using the TS's ability to strike fear in the hearts of officers. Commander Toreth is willing to only follow Rakal's orders so far and makes it clear that the miltiary can push back if push comes to shove (the reaction to the Corvallen freighter's destruction also makes it clear the military isn't fully under the TS's yoke).
As a result, we can presume that every Romulan ship has at least one TS agent on board, possibly several. The bulk of the crew, however, is almost certainly members of the Romulan military: presumably the Tal Shiar leaned on an Admiral to get a number of warbirds (5 isn't really all that many) absconded for a secret assignment. The commanders and crews could easily have been selected to be willing to go along with what, as far as they know, is a legitimate Romulan/Cardassian military exercise. The OO doesn't have that luxury: they aren't allowed warships and they aren't allowed to force the Central Command to obey their orders. Remember that their fleet was completely unknown to Dukat and the Central Command in "Defiant", meaning that the entire crew of those ships were all OO agents.
And now suddenly everything fits into place: the Tal Shiar, despite shapeshifter!Lovok's brave front, didn't really lose that many people: their middle ranks were probably mostly represented on those warbirds, but I can't imagine more than a couple dozen operatives would be assigned to this mission. Unlike the OO, they don't need to be there: the Romulan Navy provided the ships and the personnel. The Obsidian Order, meanwhile, was probably for the most part on those ships, including Tain who had recently resumed his "head of the order" post. In fact, the whole point of "Improbable Cause" (the previous episode where Garak was almost killed) was that Tain was burning all his bridges and getting rid of anybody involved with the OO who could challenge him for leadership. Which is to say that not only did the OO lose thousands of their people, but the entire upper echelon of the organization was wiped out.
This also aligns well with the aftermath: ignoring Star Trek Picard (as well we should‡), the Tal Shiar were still operating three years later when Senator Vreenak mysteriously died in a shuttle accident that turned out to be Dominion sabotage...and if you believe that I have 85L of biomimitic gel to sell you. In DS9's final season episode "Inter Arma Enim Silent Leges" the TS were similarly still active and involved in Romulan politics. They were also featured in a Star Trek Voyager episode for completely insane reasons, when the Dominion would have been a much more fitting adversary (which, come to think of it, means Sisko shouldn't feel bad about the events in "In The Pale Moonlight" one iota). The Tal Shiar is doing fine. Lovok died, yes, but he was only a Colonel rather than the leader of the organization, and he died long before this incident anyways.
The Obsidian Order is doing far less fine: their de facto leader in Tain is dead. Their most capable upper leadership alternatives were all executed by Tain before he entered the wormhole. Thousands of operatives are dead, and since they were the ones operating the ships we can presume they were pretty capable ones. They have been utterly exposed as violating their rules of operation. What happens to the secret police when they get essentially neutered? Well, we saw what happened in the sprawling DS9 season 4 opener "The Way of the Warrior": the old Detapa Council was replaced by rioting civilians with a new one. Garak explicitly notes that this was due to the OO's destruction, which makes sense: without their secret police holding the citizenry in fear, the only force protecting the old council and their entrenched interest is the Cardassian Military. As Dukat observes later in that episode, the Central Command serves the Cardassian Government and simply has to work with whoever the new kids in town are. We've seen that the Central Command is still at the whim of their leaders: even before "The Way of the Warrior" the Central Command had to honour the DMZ (they had to disrupt events in secret), withdraw from Bajor, and even make nice when Ben and Jake showed up in a Bajoran sailing ship.
‡ Star Trek Picard's sins are legion, I understand, but one of them is superseding the Tal Shiar with an "even more secret police" called the Zhat Vash. The "even more secret" doesn't really bother me: the British "secret police" group MI-5 was public knowledge in 1970, but the existence of MI-6 was hotly denied up until 1994 (when it's very public headquarters was dedicated by HRH Queen Elizabeth II...that building by the way was designed by a Sir Terry Farrell). What's really unforgivable is the name, with all its harsh consonant sounds it sounds much more Klingon than Romulan.
So there you have it: Chris Bennett's objections to how the two intelligence agencies were "wiped out" have been satisfied. He sort of stumbled upon it with his (slightly inaccurate) "1/3 of the government" comment, but didn't look at the established evidence about how each intelligence operation worked. It's worth noting that on the same Tor page another user, Jarvisimo, mentions the novel The Never-Ending Sacrifice by Una McCormack. In that novel, the OO is so badly decimated by the loss of personnel that they lose their effectiveness and therefore civilians can seize power from the previous Detapa Council.
