Nutshell: I can definitely see what they were going for here, but the way it's assembled feels a little too forced and sudden.
"For the Cause" is a story that almost works on so many levels, but it ultimately doesn't quite come together because the characters are at the mercy of a plot with so many collusively entangled angles that they're constantly being jerked here and there without real justification. This is too bad. I get the feeling this story would have been much stronger if it had either dropped some of the extraneous baggage or been a little more truthful about it.
Odo and Eddington come to Sisko after a staff meeting and tell him they have reason to suspect that Kasidy Yates is smuggling supplies for the Maquis. This happens, no less, after a scene that reveals to us that Ben and Kasidy have reached consummation in their relationship. So now Sisko has to deal with the emotional repercussions of finding out his lover isn't what she seems while performing the difficult duty of uncovering her motives.
Ah, the Maquis—now here's a plot line we haven't seen in any real detail since the second season. So much has happened since then—the Dominion's foreboding, the Klingons' presence, the Cardassians' woes. In fact, one thing I was hoping "For the Cause" would explain is what exactly the Maquis do now that political situations have so considerably changed. They are, after all, terrorists for a reason. Unfortunately, the show doesn't explain anything new; it just keeps the general idea in the air that the Maquis are simply not happy with their situation and that they're going to be trouble. (Wouldn't the Klingons' seizure of colonies lead to skirmishes between the Maquis and the Klingons? That would be an interesting angle, but the episode doesn't begin to ask such questions.)
The core of the episode centers around Sisko's dilemma of what to do when he discovers that the woman he loves has a hidden agenda. This part of the story is solid, believable, and empathizing. Sisko is justifiably skeptical of Eddington and Odo's suspicions at first. At the same time, it's obvious that he won't look at Kasidy again without wondering what she's hiding. The personal consequences of the events definitely make for relevant drama.
Still, there are some missed opportunities here, particularly because of Sisko's unwillingness to open up to anybody about his troubles. There's a nice scene between Sisko and his son (I thought the "Things change, but not this" bonding was quite poignant), yet I can't help thinking how much nicer the scene could've been had the writers allowed Sisko to talk to Jake about his problem. Similarly, the same goes for the scene where Dax is going to offer her ear after a briefing—Sisko's "Dismissed, Old Man" conveys his brooding state, but good dialogue could've conveyed so much more.
But there's more here than just Sisko's personal affairs. There's a plot involving some costly industrial replicators that the Federation is shipping to Cardassia as part of a relief program, and Eddington thinks the Maquis may try to obstruct such an effort. So while Eddington makes special security preparations at DS9, Sisko takes the Defiant, cloaks it, and follows Kasidy's freighter into the badlands where she's expected to rendezvous with another Maquis agent. The other agent, however, never shows up, and the Defiant ends up waiting hours for the illegal transaction to take place.
Something is fishy—as Odo points out, smugglers don't wait around if their buyers don't meet them on schedule. Sisko and crew decloak and beam over to Kasidy's freighter, and then they realize that they've been had—the whole thing was a trick to draw Sisko away from the station so someone could steal the industrial replicators.
It's about here where the plot introduces one device to many. Something about the whole thing feels off-kilter. The thief turns out to be Eddington—a Maquis spy himself—who stuns Kira and takes command of the station so he can sneak away with the replicators while half the command crew is still hours away on the Defiant. Sisko & Co. rush back to the station without Kasidy's ship but they're too late—Eddington is long gone.
This ending, alas, feels very wrong. I think the biggest problem is that all of these plot developments simply don't seem justified by the rationale of the characters. Eddington's defection is supposed to be shocking, but it isn't—it's just unwarranted. When Eddington contacts Sisko, he rants on and on about the Federation and what it represents, even calling it worse than the Borg ("At least they tell you they're going to assimilate you"). Kenneth Biller's performance seems sincere, but this does not work because it comes so far out of left field and feels so forced. (When was the last time we even saw this guy anyway? "Our Man Bashir"—which is completely irrelevant in terms of this show.) The story never explains why Eddington is so taken by the Maquis' plight, or why he's so angry at the Federation. It's as if the writers are pulling this stuff out of the air.
For that matter, the same goes for Kasidy Yates—though her role doesn't feel nearly as excessive as Eddington's does. (She doesn't rant about the evil Federation and so forth—it appears that she's just a sympathizer). While the idea of Kasidy putting Sisko in this painful situation is fine, the story's explanation of why—practically none—is far from fine. I did, however, appreciate the fact that Kasidy turns herself in for Sisko's sake, and that Sisko is able to forgive her even if he has to send her to jail.
I might take some comfort in the way this episode played out if I thought we would see any consequences of it. But the way the show is presented, I highly doubt we will see Eddington or the Maquis anytime soon—and that's irritating. The story should've stuck with the Sisko/Yates angle and considered it more deeply. By adding the thread involving Eddington, the plot shoots itself in the foot and seems like little more than a device to write out two of the series' recurring characters.
As for the B-story involving Garak and Tora Ziyal, it meanders too much without much of a point. Garak's scene with Quark where Kira threatens him is sort of amusing, but the scenes between Garak and Ziyal (who was unfortunately recast with Tracy Middendorf—a lesser performer than Cyia Batten) mostly fall flat. It's your standard filler—inoffensive but hardly compelling.