Sentence:  Looking back at the unprecedented meddling of European powers in his country's politics amid the Euro crisis — a series of events that led to his fall as well as Greece becoming the first country in the zone to be forced to accept painful austerities in exchange for bailout loans — Papandreou told TIME, "I think it couldn't have been avoided. We were a <WSD>lab rat</WSD>, an experiment." 
Meaning of the word marked with <WSD> tags:  A person or group used as the subject of an experiment or test, especially unwillingly or unwittingly.