I think that Crusade was actually against Averoth and Caerwyn became collateral damage when they picked the wrong side, but we might very well have declared a separate Crusade against Caerwyn. They expressed some serious hostility toward Sanguis Astroism in the course of breaking the federation with Astrum and siding with Averoth and basically proclaimed their intention to push us out of the west, so we would certainly have had sufficient cause for a Crusade.