Which ones are divisive force and which ones are unifying force ?

Unifying forces, in theory, include pan arabism and pan Africanism. African independence movements have been divisive e.g. biafra, and the recent split of sudan. Zionism has been divisive because it introduced a pariah state into the Mideast; arab opinions on how to deal with it vary so much. Balkan conflict was divisive of course. Indian independence movements led to the split of pakistan away from India following independence in '47. Despite recent strife, Islamic fundamentalism might be considered a unifying force because it can encompass a number of states or groups (it unified the iranian opposition to the shah around 1978).