A fascinating Foreign Affairs article 'The Estonian Spymasters: Tallinn's Revolutionary Approach to Stopping Russian Spies':http://www.foreignaffairs.com/articl...masters-000000

The title comes from this comment by Estonia's President:
We caught four moles in the last five years....That means one of two things. Either we’re the only country in the EU with a mole problem, or we’re the only country in the EU doing anything about it.