Without peace and aid from the Federation, the Empire will collapse/break up. Now this isn't some internal last-second coup that we may have seen when the USSR was about to break-up. This is a long drawn-out plan with aid from Federation conspirators*. What exactly is Chang (who doesn't seem stupid) and friends plan? You could say, he wasn't thinking that far ahead, but the very nature of the length of time it takes to make a conspiricy makes that unlikely. These aren't your normal block-headed TNG Klingons. *Also the Federation conspiracy makes sense. You can help the Klingons and have them rise up again to possibly conquer you. Which DID happen in one reality based on the most tenuous of events, and then there was the Accords being torn up in the Dominion Events. OR, you can let them collapse under their own weight, completely from their own hubris. Thus legitimizing your own political way of life for everyone to see. and it makes perfect sense a Vulcan was involved. Instead of being all pissy, she should have just said what I just did. And I hope the Romulan ambassador wasn't worried. It makes even more sense from his point of view. They should have been the ones to come up with the idea. Maybe the Romulans promised to help Chang and then would have pulled the rug out.