He explains this very point elsewhere in his article
The answer lies in the tragic errors of the left. The far left, a force to be reckoned with in France, was unable to unite and present a single candidate. No fewer than three Trotskyist candidates, a Communist and the altermondialiste José Bové were competing for the votes of the same constituency. Their disunity rendered their campaign inaudible
And he doesn't explain why the far-left can't unite! "Dieu se rit des hommes qui se plaignent des conséquences alors qu'ils en chérissent les causes" Jacques-Bénigne Bossuet
