This would be Pre-52 characters
It would probably happen in an alternate universe where their morals are twisted form of the mainstream heroes.
Batman takes some inexperienced members of the Justice League to rescue one of the main 7 that has been captured(Aquaman) because all of the other leaguers are busy
Some of them are killed on this mission
Superman and Batman have a falling out over how the Justice League should be run
They each have mix of Wolverine's and Cyclops' views of the situation
They split the JLA in half
One side goes after villains without killing them and they train new recruits at a gov.-sponsored school(Led by Superman)
The other side goes after villains willing to kill while training new recruits on the job. They are willing to sacrifice their own members to save many other lives(Led by Batman)
Do you agree with the side that I placed Batman/Superman as the leader of?
Which side would the other five members join?
What other JLA members would join Batman's side?
What other JLA members would join Superman's side?
I think that WW and Aquaman would be on Batman's side and MM, GL, and Flash would be on Superman's side
I don't feel like posting my opinions for the sides of the 20-30 other members. That is your job.