. Still, there was very likely a changeling among the Breen, what with that prisoner at Camp 371. The only other prisoners were survivors of the battle over the Founder's homeworld, and the rest - Martok and Bashir - were definitely impersonated by changelings. It's probable that the Breen prisoner was impersonated, too. Still, that changeling may have had no impact on the Breen's decision to join, or perhaps only had to say something like "Hey, we should side with the Dominion!" and the rest of the population said "OK!"