[1] Made in the name of patriotism, it stood in opposition to the pledge made by the French Section of the Workers' International (SFIO), internationalism, and its former leader Jean Jaurès not to enter any "bourgeois war".
[2] Although an important part of the socialist movement joined the Union sacrée, some trade unionists such as Pierre Monatte opposed it.
The next day, Prime Minister Rene Viviani read an address written by President Raymond Poincaré: This political movement may have been an attempt to create solidarity during a time when the largely pacifist SFIO threatened a general strike, while many French Catholics were slighted by anti-Catholic policies, such as the separation of church and state.
Elements of nationalism, that the Germans attacked rather than the French, anti-German propaganda, and a desire to regain the former French territory of Alsace–Lorraine may have provided further impetus for the movement.
Similar movements existed in other countries, such as the Burgfriedenspolitik in Germany or the União Sagrada in Portugal.