Geography matters. Although it doesn't matter as much to the nuclear proliferation argument because it really doesn't matter where you're located because you are affected in some way, geography matters in NATO. It has a geographic name. We have to know that it can't be all-serving around the planet and serve in theory in what they call regional security complexes, this idea that particular regions evolve against a common threat and they will strengthen and solidify the ways and means to protect themselves.
Where two groups have always been fighting one another, if there's a common threat to both of them, they will work together and create a security complex to be able to counter the threat. NATO in a way can't necessarily be everywhere because it's intended to serve the countries from a geographical position around the north Atlantic. I just want to put that in there because I am a political geographer.