How much NATO expansion is enough?

One would hope that stories like this one would prompt a bit more caution among those leading the charge to expand NATO further eastward. If the alliance extends membership to nations like Georgia and Ukraine that share borders with Russia, it will automatically become a party to numerous conflicts and rivalries that are of little interest to the West but of great interest to Russia, a nation that we sometimes forget remains a great power with a great capacity to cause mischief. That doesn't mean that we should simply let the Russians have their way in the region or that we shouldn't seek some sort of security partnership with Russia's neighbors short of NATO membership. But neither does it mean that we should pursue NATO expansion in a way that is needlessly provocative and that doesn't even serve our own interests.