After this experience de Mun dedicated himself to advancing the Church's teaching in French society and supporting the working class.
As an advocate of social Catholicism de Mun was initially a Legitimist, before supporting the Third Republic following Pope Leo XIII's encyclical Au milieu des sollicitudes.
On the surrender of Metz, he was sent as a prisoner of war to Aachen (Aix-la-Chapelle),[5] where he met René de La Tour du Pin.
The influence of the Church was exerted to secure his election and, during the proceedings, he was awarded the Order of Saint Gregory the Great by Pope Pius IX.
Within a few weeks de Mun established himself as the leading defender of the Church and earning the respect of the anti-clericals with his oratory and strong personality.
[9] He spoke strongly against the exile of the French princes (after the Count of Paris gave rise to suspicions that he was preparing to claim the throne), and it was chiefly through his influence that the support of the Royalist party was given to Georges Boulanger.
As a faithful Catholic, he obeyed the encyclical of 1892, Au milieu des sollicitudes, and declared his readiness to rally to a republican government, provided that it respected religion.
In Durmont's newspaper La Libre Parole the count and Papal Nuncio Cardinal Domenico Ferrata were denounced liked common criminals.
In 1897, he succeeded Jules Simon as a member of the Académie française, owing to the quality and eloquence of his speeches which, with a few pamphlets, form the bulk of his published work.
This was reinforced by his antisemitism believing the Jews were plotting an international conspiracy and casually referred to them as youtres (French equivalent of "kikes").
The Count's denouement led him to make common cause with his political rivals Jean Jaurès and Georges Clemenceau, along with the Republican historian Ernest Lavisse.
However, exhausted by his work, the last election, and his illness, de Mun was dismissive of the significance of the assassination of Archduke Franz Ferdinand in 1914.
[23] Despite their often-bitter political differences de Mun condemned the Assassination of Jean Jaurès sending a "touching" letter to his widow expressing his condolences.
[25] Outside the chamber another of de Mun's former enemies Théophile Delcassé, who had engineered France's break with the Vatican, was receiving congratulations for success in forging the Entente Cordiale.
Prime Minister René Viviani responded by authorizing de Mun to recruit 250 priests for service, but without pay and for an indefinite length.
[27] At the end of August Poincare urged Viviani to broaden his ministry by bringing in Aristide Briand, Alexandre Millerand, and de Mun.
De Mun, who was disappointed that his age and health prevented him from rejoining the fight was thrilled by the decision for it allowed him to work directly with the army again.
Furthermore, his daily wartime editorials significantly improved morale with the War ministry flooded with messages from soldiers and citizens praising the Count's writings.
[28] Confident in the ultimate victory of Marshal Joffre, de Mun had to be ordered by President Poincare to leave Paris with the rest of the government for Bordeaux.
In an extraordinary break with precedent President Raymond Poincaré, Prime Minister René Viviani, Delcassé, and the majority of deputies and senators attended the service.