Europe is learning that you can’t separate trade and politics

For all the jibes about it being a protectionist bloc, the EU has long been an important force for deeper international trade. The cross-border integration of its own members’ economies is the deepest in history. Internationally, it is the most open economic region. Trade, together with competition, is the bloc’s most successful policy area.

It has achieved this by giving negotiating power to an executive — the European…