1. It won't, but if we don't then we'll send a message to the Quadrant that the Federation will do nothing if you assassinate one of our Ambassadors.
2. We can take them. But more seriously, we're already at sorta-war with the Cardassians. They agreed to limit the scope of the war for a reason, and I doubt they'll expand it just because an annoying client state bit off more than it could chew.
We don't need to raid their colonies or anything like that. Just send a few ships into their home system, blow up unmanned satellites and outposts, and read them the riot act.
Waitaminute. Remember that the main thing
Cardassia got out of the Treaty of Celos was our promise not to make diplomatic approaches to their affiliates. The Cardassians cared about that enough to concede some fairly important things and to completely abandon their pre-Celos policy of violently harassing us with Sydraxian raids and such.
Why do you think they cared?
Because they're having very real trouble maintaining a coalition/empire strong enough to oppose us. They
rely on the combination of Lecarre spies, and Sydraxian and Dawiar military threats to our flanks, potentially bolstered by the Yrillians, to balance out the greater size and economic power of the Federation. Those props hold up their empire like the legs of a table. Anything that threatens to break one of those legs could potentially send the whole thing tipping over. So they're not going to react well to the idea of us going on some kind of crusade against the Lecarre. If we hit them hard enough to matter, we're also hitting them hard enough to threaten the only thing about the Treaty of Celos that gives them any benefit for
respecting the treaty.
That particular Oberth is so good that it's more effective and tougher than a Centaur-A, a ship five times its size. It compares favorably with a Connie-B for goodness sakes.
We would have to promote her to the Cheron, an Excelsior, or the EC if she wanted an upgrade.
Uh... huh. I don't remember when
T'Mir got kicked up to a Veteran ship. Wow. That is actually quite badass, although we can't ever risk that ship in combat without a high likelihood of losing enough crew to render the ship ineffective.
Hey, it worked for Rogue One!
The Empire had no incentive to hide where it kept its secure datacenter, since the facility was virtually unattackable. Even then, as I understand it, it took a fair amount of captured inside information by Rebel infiltrators and sympathizers to even know that the Death Star plans would be kept there. By contrast, the Lecarre have every reason to hide their main datacenters because they
know we could theoretically blitz them at any time, and we have zero or very few insiders, infiltrators, or sympathizers among their people.
No contact with the rest of the diplomatic service, family, friends, business associates, ... ? No one had questions? For three years? Where did the Lecarre get this amount of background info? Telepaths? Obsidian Order? ... ?
I'm guessing 'telepaths,' since we now know that the Cardassians have at least one affiliate who have empaths and possibly at least a small number of trained telepaths. If so, the synergy between the Lecarre and a bunch of psychics is
much more dangerous than either the Lecarre or the psychics would be alone.
Even a few rogue Vulcans willing to do intrusive mind-melds on people the Lecarre wanted to replace, then meld the information into the infiltrator's brain, would be a problem, for instance.
I'm sure that was part of the mission, but I doubt that was the only part of the mission. As an ambassador, he's in a unique position to sow doubt or provide for malcontents, like the anti-vaxers that tried to mine us...
The catch 22 of having someone in a high position is that you only get one shot at really using that high position, so odds are that spy followed the letter of his orders and violated the spirit of them... which is completely counter to the UFP and still makes us look bad
The thing is, the Lecarre must have walked a fine line between doing poorly (to undermine the Federation) and doing so poorly that he'd be investigated and either unmasked or forced into retirement and rendered useless as an intelligence source for the Ashalla Pact.
I suspect that the infiltrator just put in an 'uninspired' performance, one that might have had FDS officials sighing and going "he's not the chan he used to be." Not an actively sabotage-ey one that would have them going "what the hell is he doing?"
Remember that the main value of a deep cover infiltrator like this is
information. The Lecarre are so paranoid and were originally so desperate to learn 'the real deal' about our culture that they were willing to beam suicide teams onto the
Sarek to read the computer core. They want to
know far more than they want to sabotage us or interfere with us.
It may well be that some level of infiltrate-and-replace behavior is actually normative among Lecarre internal politics because it's the only way organizations can really understand each other- they don't believe in the possibility of connecting with someone you
don't have spies on.
Given what's been written about the Lecarre, it actually wouldn't be hugely surprising to discover their paranoia has reached KGB levels demanding One Big Facility that can be guarded as closely as possible. But it would not be a convenient target for a retaliatory strike because it'd probably be within three kilometers of the capital building.
By the same token, it's also very possible that the location we
think is their capital and their central heavily guarded intelligence facility is actually a massive decoy that even 99.9% of the Lecarre public has been fooled by, and that the
real capital facility is in a very different place, buried far underground, maybe even on a different planet or something.
