The euro has always been a political project, despite economic theories claiming mutual benefits for member nations.
The Political Core
Euro is and always was a political project. This supposedly obvious to anyone who has moved beyond playing with their own Lego blocks after finishing eight years of school.
Political architects of the common European currency ensured their work had a solid economic foundation. This foundation continues to underpin the vast body of economic literature from the 80s, 90s, and the turn of the century.
Economic Justifications
This literature relies on works by renowned economists like Robert Mundell, Robert Barro, and David Gordon.
Their studies form the basis for the belief that an optimal currency area is possible and that long-term effects of monetary integration for participating countries would be, at worst, neutral, and potentially even beneficial to integrating economies.