thanks for sharing. but i feel that after reading his Wikipedia entry this guy also had somewhat difficult ideas to put it mildly.
https://en.wikipedia.org/wiki/George_F._Kennan
not saying that the particular ideas discussed in your linked article are wrong though. i guess they make sense from a us-centric, realist perspective. what is, in my mind, often missing from discussions about NATO expansion is that the new members wanted to join NATO. given how the Soviet Union/Russia treated those countries in the past, i can hardly blame them.