I am actually less interested in fights between different sects of any particular religion.
I believe it is exactly this fight that poses the greatest residual global security challenge, and we should probably spend some time thinking about what:

1) The non-Islamic world is going to do to address it.
2) Whether there is a particular side the non-Islamic world wants to be on.
3) If there is anything that can or should be done to minimize the fractures in Islam, or at least support proxies working to resolve the problem.