From a general legal standpoint, Worf's slaying of Duras is a pretty open-and-shut case. It's a Klingon citizen killing another Klingon citizen in accordance with Klingon law aboard a Klingon vessel. The fact that that Klingon citizen happens to also hold Federation citizenship is irrelevant, as there's apparently no law against Federation citizens killing anyone when they're outside Federation territory, only laws against anyone (Federation citizen or foreign citizen) killing anyone (Federation citizen or foreign citizen) in Federation territory. The Federation Department of Justice, it would seem, has no more right to prosecute Worf for killing Duras than it had a right to prosecute Duras for killing K'mpec.
Starfleet, however, would have had a right to punish Worf for violating any Starfleet codes of conduct he might have agreed up. It is possible that the Starfleet Code of Military Justice (aka, military law) might have provisions against officers killing people in extra-territorial situations (i.e., while on foreign territory). However, it is also possible that Starfleet military law does not prohibit homicide while on foreign soil if it occurs in compliance with their host government's laws.
Further, we also know from episodes like "Amok Time" that there are circumstances within Federation law and Starfleet military law where Federation citizens/Starfleet officers can engage in homicide if it's part of a consensual duel. It is plausible that the Federation has a general law about consensual duels ending in homicide being legal in Federation territory, given that no one placed Spock under arrest when they thought he'd killed Kirk in "Amok Time," and that we generally don't hear about Federation grand juries being convened any time someone gets killed in the kal-if-fee ritual on Vulcan.
Assuming that Starfleet military law does not prohibit consensual homicide, or that it does not forbid homicide if it occurs outside Federation territory but in accordance with the host government's laws, then the question becomes whether or not Worf's participation in a Klingon duel might in some way constitute conduct unbecoming of an officer, even if it is not strictly illegal. Worf might get reprimanded, even if he's not court-martialed.
As for Worf's killing of Gowron? The same basic issues apply... with one complication:
Starbase Deep Space 9 may have been administered as a Federation starbase, but it was Bajoran territory. So in addition to the Starfleet Code of Military Justice, there's a question about the application of Bajoran law. Does Bajoran law allow for consensual duels ending in homicide? Maybe sections of DS9 set aside for Klingon government officials were given temporary extra-territorial status like an embassy. Or maybe by Bajoran law, Worf committed murder, and he could be indicted by a Bajoran grand jury and have to stand trial in a Bajoran court.
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As for the original post....
Seems to me that Picard in "Encounter at Farpoint," and in much of early TNG, is justifiably proud of the social progress Earth and the Federation have made by the 24th century. The problem, however, comes from what seems like an attitude that this progress is a result of some sort of fundamental change in Human (and presumably, Vulcan, Andorian, Tellarite, etc.?) nature, rather than as the result of an evolution of the social structures in which they live. This leads to a lot of smugness, to a lot of prejudice against cultures they deem as too similar to their ancestors' cultures, and to a lot of hubris, a blindness about their own moral fallibility.
Starfleet, however, would have had a right to punish Worf for violating any Starfleet codes of conduct he might have agreed up. It is possible that the Starfleet Code of Military Justice (aka, military law) might have provisions against officers killing people in extra-territorial situations (i.e., while on foreign territory). However, it is also possible that Starfleet military law does not prohibit homicide while on foreign soil if it occurs in compliance with their host government's laws.
Further, we also know from episodes like "Amok Time" that there are circumstances within Federation law and Starfleet military law where Federation citizens/Starfleet officers can engage in homicide if it's part of a consensual duel. It is plausible that the Federation has a general law about consensual duels ending in homicide being legal in Federation territory, given that no one placed Spock under arrest when they thought he'd killed Kirk in "Amok Time," and that we generally don't hear about Federation grand juries being convened any time someone gets killed in the kal-if-fee ritual on Vulcan.
Assuming that Starfleet military law does not prohibit consensual homicide, or that it does not forbid homicide if it occurs outside Federation territory but in accordance with the host government's laws, then the question becomes whether or not Worf's participation in a Klingon duel might in some way constitute conduct unbecoming of an officer, even if it is not strictly illegal. Worf might get reprimanded, even if he's not court-martialed.
As for Worf's killing of Gowron? The same basic issues apply... with one complication:
Starbase Deep Space 9 may have been administered as a Federation starbase, but it was Bajoran territory. So in addition to the Starfleet Code of Military Justice, there's a question about the application of Bajoran law. Does Bajoran law allow for consensual duels ending in homicide? Maybe sections of DS9 set aside for Klingon government officials were given temporary extra-territorial status like an embassy. Or maybe by Bajoran law, Worf committed murder, and he could be indicted by a Bajoran grand jury and have to stand trial in a Bajoran court.
* * *
As for the original post....
Seems to me that Picard in "Encounter at Farpoint," and in much of early TNG, is justifiably proud of the social progress Earth and the Federation have made by the 24th century. The problem, however, comes from what seems like an attitude that this progress is a result of some sort of fundamental change in Human (and presumably, Vulcan, Andorian, Tellarite, etc.?) nature, rather than as the result of an evolution of the social structures in which they live. This leads to a lot of smugness, to a lot of prejudice against cultures they deem as too similar to their ancestors' cultures, and to a lot of hubris, a blindness about their own moral fallibility.