Trained in law, Poincaré was elected as a Deputy in 1887 and served in the cabinets of Dupuy and Ribot. In 1902, he co-founded the Democratic Republican Alliance, the most important centre-right party under the Third Republic, becoming Prime Minister in 1912 and serving as President of the Republic from 1913 to 1920. He purged the French government of all opponents and critics and single-handedly controlled French foreign policy from 1912 to the beginning of World War I. He was noted for his strongly anti-German attitudes, shifting the Franco-Russian Alliance from the defensive to the offensive, visiting Russia in 1912 and 1914 to strengthen Franco-Russian relations, and giving France's support for Russian military mobilization during the July Crisis of 1914. From 1917, he exercised less influence as his political rival Georges Clemenceau had become Prime Minister. At the Paris Peace Conference, he advocated Allied occupation of the Rhineland for at least 30 years and French support for Rhenish separatism.