But Iceland has decidedly not been stable. They gained de facto independence in 1918 and completely lost their sovereignty only 22 years later when Britain occupied them (that is despite them still having armed forces in 1940). Since WW2 things have obviously been stable-ish (things were really bad in 2009). How long do you think that would last once Iceland tried to exercise their sovereignty, for instance by leaving NATO?

Analogously, how long did the Shire last against a motivated attacker with comparatively little resources?