Yes, but breaking the pact will have negative consequences.
Errrr... what about now? My mind tells me it's going to be a trap, just not sure where.
I'm in the faction of "covertly back the uprising, wipe out the corrupt nobility with the rebels (note that the Lancafews actually tried to curtail the worst parts of slavery, but the nobility said "no"), negotiate a peace between House Lancafew and the rebels, and have Palasha (instead of her entitled loser of a brother) inherit the throne as a puppet regime.
... Does this count as "waging war against Dorgania"?