In 1926, he received the Nobel Peace Prize along with German Foreign Minister Gustav Stresemann for the realization of the Locarno Treaties, which aimed at reconciliation between France and Germany after the First World War.

The ministry of Maurice Rouvier was allowing disturbances during the taking of inventories of church property, a clause of the law for which Briand was not responsible.

As opposed to Jaurès, he contended that the Socialists should co-operate actively with the Radicals in all matters of reform, and not stand aloof to await the complete fulfillment of their ideals.

[9] Le Trait d'Union Orient de Saint-Nazaire lodge had declared him "unworthy of belonging to the great masonic family on 6 September 1889".

[citation needed] At the end of August 1914, following the outbreak of the First World War, Briand again became Minister of Justice when René Viviani reconstructed his ministry.

In the winter of 1914–15 Briand was one of those who pushed for an expedition to Salonika, in the hope of helping Serbia, and perhaps bringing Greece, Romania, Bulgaria and Italy into the war as a pro-French bloc, which would also act as a barrier to future Russian expansion in the Balkans.

[15] Draft proposals for Allied cooperation, prepared by Lord Esher and Maurice Hankey were on the table by the time British Prime Minister H. H. Asquith visited Paris on 17 November (mainly to discuss Greece, and only his second wartime talks with France; the first had been with Viviani in July 1915).

[16][17] In the poisonous atmosphere after the opening of the German attack at Verdun (21 February 1916), Gallieni read an angry report at the Council of Ministers on 7 March criticising Joffre's conduct of operations over the last eighteen months and demanding ministerial control, then resigned.

[20] The first formal Allied conference met in Paris on 26 March 1916 (Italy did not participate) but initially made little impact, perhaps because Briand had vetoed the British suggestion of a permanent secretariat,[21] or perhaps because there had been three informal sets of Anglo-French talks in the last quarter of 1915, one of which, the Chantilly meeting, had already seen strategy plans drawn up.

[25] Late in 1916 Roques had been sent on a fact-finding mission to Salonika after Britain, Italy and Russia had pushed for the dismissal of the theatre commander Sarrail.

Coming on the back of the disappointing results of the Somme campaign and the defeat of Romania, Roques' report further discredited Briand and Joffre and added to the Parliamentary Deputies' demands for a closed session.

That day his government survived a vote of confidence by 30 votes, and Joffre was appointed "general-in-chief of the French armies, technical adviser to the government, consultative member of the War Committee" (he was persuaded to accept by Briand, but soon found that he had been stripped of real power and asked to be relieved altogether on 26 December), with Nivelle replacing him as commander-in-chief of the Armies of the North and Northeast.

[32] Briand resigned as Prime Minister on 20 March 1917 as a result of disagreements over the prospective Nivelle Offensive, to be succeeded by Alexandre Ribot.

The Conference agreed on the American proposal that capital ships be limited to a ratio of 5 to 5 to 3 for the United States, Britain, and Japan, with Italy and France allocated 1.7 each.

Pressured into a game of golf by David Lloyd George he played so badly that opposition factions in the National Assembly were able to portray him as both inept and a British sycophant.

[citation needed] Briand negotiated the Briand-Ceretti Agreement with the Vatican, giving the French government a role in the appointment of Catholic bishops.

[37] Described as Briand's Locarno diplomacy and as an aspect of Franco-German rapprochement, it was his answer to Germany's quick economic recovery and future political power.

The plan, under the Memorandum on the Organization of a System of European Federal Union, was in the end presented as a French initiative to the League of Nations.

With the death of his principal supporter, German foreign minister Gustav Stresemann, and the onset of the Great Depression in 1929, Briand's plan was never adopted but it suggested an economic framework for developments after World War II that eventually resulted in the European Union.