Nutshell: Some interesting director's techniques and a marvelous ending, but the story and courtroom scenes are completely routine.
Klingon prosecutor Ch'Pok (Ron Canada) heads an extradition hearing against Worf (defended by Sisko), who he wants to bring back to the Klingon Empire to answer for a severe charge. The charge: Worf is accused of wantonly destroying an innocent Klingon commuter ship which suddenly decloaked in the middle of a battle between the Defiant and some hostile Klingon vessels. It was a tragic accident in any case—441 defenseless Klingons were killed. However, the details are clear and confirmed: There were only seconds to react, and Worf's order to fire seemed justifiable under the circumstances of the battle.
Ch'Pok, however, does not intend to argue the facts. He intends to "put Worf's heart on trial"—to prove that because Worf is Klingon, his boiling blood got the best of him, causing him to open fire without thinking things through. In turn, Ch'Pok argues that since Worf's heart is Klingon, he should be extradited.
"Rules of Engagement" is an episode like many in the second half of DS9's fourth season have been. It's a small, mostly-contained story that tries to work in elements of the larger-consequence, long-term story arc of the Klingon/Federation political situation. Consider "Return to Grace" and "Sons of Mogh," for example. Both had something worthwhile to add to the canvas, while neither were really that pressing on their own. "Rules of Engagement" is another that falls into this "relevant but not compelling" category, but it's probably the least urgent and impacting of the three because its plot really doesn't have very far to reach.
It's simultaneously a Trek Courtroom Drama, a Worf Episode, and a Web of Conspiracy. And while it's a decent, solid episode with the expectedly up-to-par performances and some nice director's flourishes, these elements simply don't come together to become anything more than an average episode with flaws that are evident, even if they're not particularly clumsy.
Really, the biggest problem with this episode is that we've already dealt with most of the issues in "Sons of Mogh." Again, we have the Federation and the Empire clashing their agendas, and, again, we have Worf on the fence, proclaiming to be a Klingon at heart with duty and loyalty to the Federation. Again, we have Klingons coming forward and telling Worf that he doesn't fit in anywhere, and, again, we have Worf proving that he can indeed maintain ties with both sides, even if he and others aren't happy with the fact.
Meanwhile, we have the extradition hearing, in which Ch'Pok uses sensational tactics to pressure Worf into active loss of his temper, much to the ire of Vulcan T'Lara (Deborah Strang), the extradition arbitrator who ultimately holds Worf's fate in her hands. The courtroom situations are adeptly written by Ronald D. Moore, and director LeVar Burton (who is becoming prolific these days) successfully pulls off an interesting technique in which flashback is used in a cross between diegetic and non-diegetic senses, as the characters in the flashback actually speak to the camera as witnesses on the stand. Still, despite these strengths, Star Trek is not Law & Order no matter how hard it tries; and sometimes "Rules of Engagement" seems to be trying almost too hard—Sisko shouts "Objection!" a little bit too emphatically on occasion, making the drama feel just a tad overly theatrical.
There's also the problematic ending, where it seems Ch'Pok may be on his way to a victory until along comes the reliable deus ex machina—Odo finds a record that proves, in fact, that the ship destroyed was not carrying innocent people; the passenger manifest is identical to that of a ship that crashed months ago. What does this mean? It means that the entire situation was staged by the Klingons in an attempt to force Starfleet from abandoning its relief effort of escorting Cardassian convoys. Uh-huh. This "revelation" is awfully unlikely and contrived for starters, and also seems rather dishonorable and "un-Klingon-like" to me. It's also an all-too-easy way of resolving the episode—using a conjured plot manipulation instead of basic story strength or character truths. At least it gives Sisko the chance to put Ch'Pok on the stand and grill him with a hypothetical situation game, which turns out to be an absolute delight thanks to Avery Brooks' delicious performance as a bombastic lawyer.
There's also a very welcome reflection scene between Sisko and Worf after the hearing is resolved. Sisko points out that Worf did indeed make some big mistakes in his command decisions, and he offers some advice. I particularly like Sisko's response to Worf's brooding behavior: "Part of being a captain is knowing when to smile." (I think it's about time Worf lightens up.) The final exchange is also nicely put:
Worf: "Life is a great deal more complicated in this red uniform."
Sisko: "Wait until you get four pips on that collar."
But one last annoyance that I want to bring up (even though it isn't crucial to the plot) is the question of Kira's rank aboard the Defiant. Even if I still don't understand the justification, I'd be willing to grant that Worf would take command over her (if, for no other reason, because Sisko ordered him to command the mission). But then the story declares that if Worf was injured, O'Brien would take command of the ship. Why is this? (Besides the obvious fact that the plot here requires it?) What is Kira's purpose on the bridge? O'Brien isn't even an officer—he's an engineer. Yet, according to this episode, he would be fighting the Klingons while Kira follows his orders. This makes no sense at all.
I like Worf's addition to the cast, but I don't like what has been happening with Kira. Her role as a strong character has seemed slighted all this season, and the way the producers seem to dance completely around the established chain of command without so much as a passing reference to it does not sit well at all.