Is France on the brink of a political revolution? Already, four established candidates for the presidency — two former presidents and two former prime ministers — have backed out or been rejected by the voters, and another, François Fillon, is on the ropes. The campaign is being taken over by outsiders, principally the Front National’s Marine Le Pen and a youthful former banker, Emmanuel Macron, while the Socialists have chosen an eccentric radical, Benoît Hamon.