At the signing of the Rome Declaration at the 60th anniversary of the Treaty of Rome, which established the European Community on March 25, 1957, E.U. leaders expressed their intention to further strengthening the federal Union. Even as “regional conflicts, terrorism, growing migratory pressures, protectionism and social and economic inequalities,” as well as Britain’s upcoming secession provided a sense of pessimism, Jean-Claude Juncker, president of the European Commission, the E.U.’s executive branch, said, “Let us not lose perspective.” I submit that this advice was at the time very important.
The full essay is at "Perspective on the European Union."
 James Kanter and Elisabetta Povoledo, “E.U. Leaders Sign Rome Declaration and Proclaim a ‘Common Future’ (Minus Britain),” The New York Times March 25, 2017.