10 Star Trek Captains Who Broke The Rules

Yes, we're talking about the poisoned planet. 

One might assume that In The Pale Moonlight might be the easy option here, but one must remember that to a certain extent (and with a healthy dose of plausible deniability) Sisko acted with Starfleet Command's blessing in those circumstances.

No, we're not sure that Garak's final actions are covered in that. But it's all very grey in that case, isn't it?

Where it isn't even remotely grey - not even a hint of dusky cream - is Sisko's decision in the hunt for Michael Eddington. The Maquis' escalation to the use of biogenic weapons is all the excuse that Ben needs to get a little trigger happy himself - although that is hardly giving events their due. 

The Maquis, with Eddington as their leader, poison Cardassian worlds so that those settlers are forced to flee. Sisko, though acting behind the veneer of keeping the peace in the DMZ, elects to return the favour to a Maquis colonized world, all while Eddington looks on in horror. 

Eddington truly has the measure of the man here - his obsession with the former security officer has pushed him beyond the limits of his duty. As Sisko later admits, he never received clearance to fire chemical weapons in the pursuit of these people. 

We're fairly certain that poisoning a planet to flush out your quarry goes against at least SOME Starfleet regulations.