Sooner or later, possibly as early as next week, France’s far-right National Rally (RN) is going to take power. That’s the main lesson of Sunday’s first round of snap parliamentary elections, in which Marine Le Pen’s anti-immigration nationalists amplified their European election score on a far higher turnout. President Emmanuel Macron’s gamble of dissolving parliament and seeking a “clarification” from voters after an ultra-short three-week campaign backfired spectacularly on his own supporters. His centrist coalition finished a distant third behind the RN and the leftwing New Popular Front (NFP) in the popular vote and looks set to keep fewer than...