Macron and Le Pen’s inevitable face-off exposes a major shift in French politics

Sunday’s first-round French presidential election follows days of chaotic, rollercoaster polling. Incumbent Emmanuel Macron’s once-comfortable lead over right-wing politician Marine Le Pen all but vanished going into the contest on April 10. While the results won’t reveal France’s next leader just yet, the election and the campaign leading up to it have exposed seismic shifts in France’s political culture that the establishment has yet to reckon with.

The run-up to the first-round elections wasn’t the first indication of that shift — far from it, according to some observers — though the...