Subadei has some interesting thoughts on the possibility of a new and hostile Core (shortly defined as a group of connected, interdependent nations) involving Iran, Venezuela. However, I think there is not much to be worried about. Assuming they do create/evolve into a second core, they would have enough incentives/core-like attributes not to do so.
I guess that raises the question, can there be two Cores? Wouldn’t the opportunity cost of maintaining the divide between the two Cores? Wouldn’t the opportunity cost of maintaining the divide between the two Cores become too costly for the divide to be sustainable?
Update:Edited for clarity