What would happen if a modern constitutional monarchy, say the UK and Norway in 1970, ended up having the same monarch? Would such a succession be blocked and viewed as illegitimate in lieu of a 'local' successor or would it create a sort of constitutional grey area?

by Leizazure

Apologies if I am not too clear, you may use England and Norway as an example of what might have happened in such a scenario.

ctesibius

That's a very common situation. For instance Queen Elizabeth is monarch of both the UK (not England, it's specifically the UK) and Canada. These are two separate crowns, and Canada could chooses to become a republic (boring) or to alter the rules of succession so that they do not align with the U.K.

Ed__

Nothing weird happens it's just a personal union.

If it's deemed undesirable one or both kingdoms would alter sucession laws.