Europeans made decisive progress on integration outside the scope of the EU treaties (but very much in the European spirit) when they agreed to open their borders with the so-called Schengen Agreement (today a part of the EU treaties). Drawing on that successful experience, the eurozone should avoid the EU’s original sin of creating a supra-national structure that lacked democratic legitimization.
欧洲曾签署过所谓的申根协议（如今是欧盟条约的一部分），开放边境，这是在欧盟条约之外（但仍带有鲜明的欧洲精神烙印）迈出的具决定性意义的统一步骤。从这一成功先例看，欧元区应该避免欧盟建立缺乏民主合法化基础的超国家结构的原罪。