The target of one of these wars is always a power that threatens national security, which most of the times is another national institution. This way, most affiliations whose interests don't match are bound to, sooner or later, engage in armed confrontation. Civil War is also disastrous ecologically because of the extent of the destruction it generates. In MMOGs, Civil Wars can be defined as an inner conflict that arises when there are mutually exclusive goals espoused by the parties, in the sense that if the goal of one if fulfilled, it will be at the cost of the other. Patton People can be mobilized towards taking 'national roles' on the basis of some significant national purpose.
National purposes have to do with differences of ideology, opposing to material objectives.
MMOGs allow a certain degree of freedom when it comes to political structures. Examples of national purposes in games would be different forms of government that player-run towns employ. I was fortunate enough to witness an example of ideological war. The other was a region where warriors dwelled, and opposing to the first city, the council demanded that new citizens paid a large sum of money to join the town - literally buying their citizenship. After a few months of coexistence, the tension between the two towns could no longer be ignored.