During the course of Deep Space 9, Sisko directly causes two wars- both the result of direct orders that he knowingly violated.
In The Die Is Cast (Season 3, Episode 21), Odo is being held against his will onboard a Cardassian ship controlled by the Obsidian Order; part of a secret Cardassian/Romulan fleet on a mission to destroy the Founder's Homeworld. At this point in the show, the Federation is more or less at a truce with the Dominion, their last encounter having been when Odo petitioned for the crew's safe release from the Founders.
Sisko expresses a desire to go and rescue Odo, but Admiral Toddman explicitly forbids it, not wanting to draw the Federation into open conflict with the Dominion (or Cardassia/Romulus). Sisko ignores this order, goes to the Gamma Quadrant, joins the battle (if only to rescue Odo), and destroys several Dominion ships. This directly results in escalation of their conflict with the Dominion to open warfare.
In The Way of the Warrior (Season 4, Episodes 1&2), the Klingons have decided to take advantage of the weakened Cardassia and launch a full scale invasion. The Federation Council explicitly votes not to get involved, and Sisko is ordered not to interfere. He once again ignores direct orders and choose to secretly leak the Klingon battle plan to the Cardassians, and even worse, later takes the Defiant to rescue the Cardassian government (and Gul Dukat), directly engaging with the Klingons and destroying a ship.
Over the course of this two part episode Sisko's actions directly result in the collapse of the alliance between the Federation and Klingons, and then cause a war between them in which thousands die. It also directly lays the groundwork for the future Cardassia/Dominion alliance (and subsequent war which costs millions of lives). Furthermore, it represents the will of a single out-of-control Captain overriding the decision of a democratically-elected body.
The show never depicts Sisko suffering any consequences for his actions. On the contrary, in between the two events described above he is actually promoted. Have the show's writers or the books ever touched on the complete lack of accountability for Sisko?