I could consider joining a united Europe, maybe...
If we basically copied your constitution and bill of rights.
Having a solid Constitution and Bill of Rights is one thing. The issue in this country is actually following it.
The US has proven that the Constitution is little protection. The courts ignore the parts that are inconvenient on a daily basis.
the ideal EU would be a confederation like that of Switzerland — so a larger version of Switzerland with individual national regions self-ruling utterly and a very, very small central government with a strict mandate about self-defense and internal security.