Quote Originally Posted by hymer View Post
I’m aiming towards a situation much like the American Civil War, with huge numbers of guys using tactics that do not fit the weapons they’re using, and battles usually having huge casualty rates.
I’d like for there to be at least three factions, two of which are hoping to achieve planet-wide dominance and one or more, which is/are basically hoping the others will wear each other out, leaving the others free to govern themselves.
First of all, I don't agree with the assertion that in the American Civil War the tactics didn't fit the weapons -- but I understand what you are saying.

The main issue is that if you want huge battles with large numbers of people fighting and dying, then you need the infrastructure to support large armies. You will need transport, communications networks, surplus food, and all the organization and bureaucracy needed to coordinate that.

Then there's the issue of the technology itself. If they don't understand it, then they won't be able to repair or replace it as it wears out. Large stockpiles of equipment will help (and may even be strategic targets), but eventually they will run out -- and they will run out quicker if you have large armies going at each other constantly. Also the technology to run farms efficiently will be stressed and gradually lost, making it harder to support large field armies. With no way to replace equipment, all factions will probably look something like the losing side of a war of attrition, except that it will look more like the end of such a war from the very beginning.

If the warfare was on a large scale, then I would imagine that it would burn itself out pretty quickly; the technology would quickly be damaged, lost, etc., and the war would grind down. If continued it would take on a much smaller scale, probably more like guerilla raids, and more antiquated weapons would be used. If the warfare was more small scale to begin with, then it could last for a long time with technologically superior weapons. In either case the amount of spare equipment available would be a factor to consider.