That's not the kind of question anyone here in the UK feels the need to ask.
Because nobody - really, nobody - is seriously considering the prospect of such a war.
But it is something at least one international military planner is imagining - albeit fleetingly - as he thinks through the consequences of Britain's potential break-up.
How they talk, what they talk, gives them their hecho diferencial, the thing that sets them apart from, respectively, other Canadians or Spaniards.
Well, not here. Scottish nationalists speak English and, usually, nothing but English. And that is a linguistic nicety that can get lost in translation.
THEY may be the pin-ups for Scottish independence but Norwegians don't know it.
Our nearest Scandinavian neighbours - by and large - remain blissfully unaware of just how big a role their social-democratic success story plays in the "Yes" case.
Norway, the nationalist story goes, has thrived since it split from Sweden more than a century ago and proved - as if proof was needed - that medium-sized nations are every bit as viable as giant ones such as the UK.