Apart from having a bigger organisation, although some members who disagreed with merging might leave, what is the attraction? Isn't there a danger that after the honeymoon period that one side would want to take over? That seems to be the case when mergers on the Marxist left have occured.  Are there examples on the nationalist side where such mergers have been successful?  The merger of the NNF and BM to form the BNP.