Keep the focus very narrow. Amish hippies?
Seriously, there's not much that you can cover is 4 to 6 pages. Not in the depth asked for.
Thinking on it, I think that you could cover "conscientious objectors" in those few pages. In truth it's as complex as anything, but it could be easily encapsulated by focusing on a few people. Check out
Conscientious objector on Wiki.