In practice, the process of integration (such as in the U.S. Constitution):

Correct answer: D. has never gone beyond a partial and uneasy sharing of power between state and supranational levels

• A. has never seen even partial success
• B. has been fully and successfully realized in the form of the European Union
• C. has never been attempted on a national level; it has only been tried on an international level
• D. has never gone beyond a partial and uneasy sharing of power between state and supranational levels