I'm using the term to mean more or less the collectively agreed upon "identity" of a state. Not merely a single contiguous government (for the same reason you just bring up, people still consider France to be France even though the government has changed fundamentally many times over the years), but I'm not using it to just mean "nation" either, since were France to be completely conquered and annexed by a foreign power, the French nation, as in the group of people, would still exist, but the country would not, at least until such time as it could be recreated, or for a different reason, that one can have a national identity split between different states, or a state involving different such groups.