Also, there was a perfectly reasonable non-Dominion explanation for the coup on Cardassia: The Obsidian Order was gone, and without them the Central Command couldn't easily silence the opposition anymore and were overthrown.
It is repeatedly stated by Sisko, quite correctly, that the Klingons do not have any proof that the Dominion is behind the coup. However, proof or no proof, the Klingon theory is very plausible, given the information available at the time. Even if you think it is probably not true, even if you figure the probability of Dominion involvement in the coup is just 20-30% (and it can’t reasonably be projected much lower), that’s not a chance the Federation or the Klingon Empire can afford to take, is it? Dominion control of Cardassia would be a disaster for the Alpha Quadrant. It would give them a huge advantage in the war that everybody knows is inevitable.
Given the Klingons’ sincere belief that the Dominion was much more likely than not involved with the coup, Sisko’s (and to a lesser extent, the Federation Council’s) demands that the Klingon sit back and do nothing is completely unreasonable. Look at it from the Klingons’ point of view. Could you possibly agree to those demands? They finally stopped only after the Federation made it clear that they would intervene militarily, which meant the Klingons had practically no hope of successfully conquering and holding onto Cardassia, and it would be foolish to sacrifice the Klingon military in a futile operation. But as long as you believe that the Dominion is involved in Cardassia and that you have a chance to do something about it, you have
to try, despite Federation protests.
Nasat, I assume those spoiler tags were intended specifically for my sake. Thank you very much, I appreciate it.
So it's OK for any military power to invade another state only on the grounds of a suspicion
against its legal government?
That logic would have allowed any power in the quadrant to wage war on just about any state they decide, with the excuse that they suspect there is a Dominion infiltration in the government, without the need to provide any proof. What if the Romulan Empire had decided to attack the Klingon Empire, stating that they suspected
with good reason that Klingon policies and their attack on Cardassia were the result of Changelings infiltrating Klingon leadership? Would that have been legitimate, too?