On the day that Britain decides whether its destiny lies within or without the European Union, I will be in California. On the surface, I could not be more far removed from the Brexit dilemma. The cool, clear Californian air seems a world away from the toxic atmosphere currently engulfing Britain. And yet, California offers a unique vantage point on the EU referendum. For the Golden State is the clearest example of a polity rendered, at times, almost ungovernable by a mania for direct democracy.