The Abbe's nimble intelligence had a weak side, which must have somewhat compromised his influence.

He was so confident in the reasonableness of his projects that he always believed that if they were fairly considered the ruling powers could not fail to adopt them in their own interests.
It is the nature of a reformer to be sanguine, but the optimism of Saint-Pierre touched naivete.

Thousands might have agreed with his view that the celibacy of the Catholic clergy was an unwholesome institution, but when he drew up a proposal for its abolition and imagined that the Pope, unable to resist his arguments, would immediately adopt it, they might be excused for putting him down as a crank who could hardly be taken seriously.

The form in which he put forward his memorable scheme for the abolition of war exhibits the same sanguine simplicity.

All his plans, Rousseau observed, showed a clear vision of what their effects would be, "but he judged like a child of means to bring them about." But his abilities were great, and his actual influence was considerable.