EU affirms unity on eve of Brexit trigger: 'Only a united Europe can be a sovereign Europe'

Leaders of the 27 European Union nations that will remain in the organization following the United Kingdom's forthcoming exit met Saturday in Rome on the occasion of the 60-year anniversary of the Treaty of Rome that established the European Economic Community, an EU forerunner. "Europe as a political entity will either be united, or will not be at all," said EU President Donald Tusk. "Only a united Europe can be a sovereign Europe."

The conference adopted the Rome Declaration, a brief statement affirming mutual "pride in the achievements of the European Union," including "common institutions and strong values, a community of peace, freedom, democracy, human rights and the rule of law, a major economic power with unparalleled levels of social protection and welfare."

British Prime Minister Theresa May, who did not attend the meeting in Rome, is expected to begin the formal Brexit process Wednesday by triggering Article 50. For more on how that process will work, see this explainer from The Week.