We already have associate options - not joining Schengen, not adopting Euro. Anything more than that results in a horrible mess of legal agreements.
Imagine that suddenly each US state gets more sovereignty and they just... make different decisions. California adopts Spanish as second official language, New York adopts metric system, Alabama permits sister/brother marriages, Utah declares Mormonism as official religion, and Wyoming stops contributing to US army. How are you supposed to do business in these conditions.
Imagine that suddenly each US state gets more sovereignty and they just... make different decisions. California adopts Spanish as second official language, New York adopts metric system, Alabama permits sister/brother marriages, Utah declares Mormonism as official religion, and Wyoming stops contributing to US army. How are you supposed to do business in these conditions.