This paper attempts to review and assess the performance of the euro during its first decade according to its original motives and to probe the emergence of the sovereign debt crises in its early years. Economically, the euro, after the single market, was seen as the missing piece in the jigsaw of European growth and competitiveness, alongside the expectation that it could compete with the dollar as a leading global currency. Politically, it was a European response to the uncertainty that resulted from the end of the Cold War and the reunification of the two Germanys. During its first decade, the euro has delivered mixed economic results and has not yet been able to challenge the dollar`s global role, while certain positive effects on the construction of European peace and social identity can be identified. Nevertheless, all these effects were counteracted by the EU`s failure in fiscal governance, which eventually led to the occurrence of the sovereign debt crises. This paper argues that the negative leadership demonstrated by Germany and France and their nationalistic behaviors in 2003 triggered the collapse of fiscal discipline in the eurozone. Evidences revealed in the euro`s first decade, again, verify the imperative of responsible leadership in European integration, which is argued to be the final answer to the prolonged crises.