WINSTON CHURCHILL’S famous maxim that “nothing in life is so exhilarating as to be shot at without result” has a political corollary: when a presidential candidate survives an assassination attempt, it can have a rallying effect. Exhilarated Republicans are making a display of this in Milwaukee, where the party formally nominated Donald Trump as its presidential nominee. Understandably, Mr Trump appears happy to have defied death. His party is also looking triumphal, with Mr Trump holding a steady lead in national polls and key swing states. Yet it is too soon to judge how durable this advantage will be.