I don't think we have an IC rationale for a civil war quite right now, and I don't think that's what is planned. However, we did that at the end of WotS and it was tremendous fun. Basically two sides arose, one loyal to the Senate (sort of), the other loyal to the Consul that Lucjan was playing at the time. econ21 GM's battles between the two sides via PMs, images, and "real" board battle mechanics. In all my years of TW, that was without doubt the most memorable series of battles ever.

But again, not sure we should go that route here. There are plenty of external forces that can be brought in.