Britain begins the day as a member of the European Union. How it ends the day will be a matter of debate that will last awhile. Will it be a proud nation that has reclaimed its sovereignty, or a diminished presence in Europe and the world? British citizens are still divided over whether Brexit is good or bad, 3 1/2 years after they narrowly voted to leave the EU. Prime Minister Boris Johnson is calling Britain’s departure “a moment of real national renewal and change” and urging the country to come together. But in Scotland, where most people want to remain in the bloc, the EU flag will be flown as a sign of defiance.