In the Pale Moonlight (Star Trek: Deep Space Nine, Season 6, Episode 19)
Captain Sisko recognizes that the Federation's war with the Dominion is costing them both money and lives. To tip the scales in Starfleet's favor, Sisko hatches a plan to persuade the neutral Romulans to join their side. He works with a former Cardassian spy and enlists the help of a criminal forger to create "evidence" that the Dominion is planning on attacking the Romulans. Things don't work out exactly the way Sisko wants them to, and he is forced to reconcile his and Starfleet's values versus the true cost of winning the war.
Watch Star Trek: Deep Space Nine on CBS All-Access.