Translate the following English sentence to French:
"However, he was unable to appreciate that the emergence of the middle classes was an element which was going to have a different effect for the first time on these elections."
Mais il n' a pas non plus su apprécier le fait que l' émergence des classes moyennes constitue un élément qui, électoralement, devait peser pour la première fois d' une manière différente sur les élections.