(Tell us about this former defense ministry official in Estonia, what has he done?) Nobody is saying much publicly except that he was charged for treason. But we can assume the worry is Russia. My guess is the Russians were interested in finding out about the programs that Estonia runs for training in the Ukraine and particularly Georgia. Estonia is a centerpiece in the former cold war. (Why would Estonia be the espionage hub of Europe?) It is a very small city, 200,000 people, but it's right on the front line of where Russian and Western interests lie. (So what kind of recourse does NATO or the U.S. have?) NATO has to start treating Russia seriously. I think it is changing a bit and I suspect NATO will start spying more on Russia and tightening its attention on that front.