The main task of Russian diplomacy was to keep the country at peace to enable the empire to carry out domestic reforms, revive its military power, and reclaim its former authority in foreign affairs. One reason for its failure was the great gap between Russia and the West in levels of industrial development. The key reform, universal military service, came about only in 1874, under the impact of France's defeat in the Franco-Prussian War. Russia supported France when the latter, together with the Kingdom of Sardinia (Piedmont), declared war on Austria in 1859. In an effort to exploit the principle of national self-determination in Gorchakov own interests, the French emperor interceded with Alexander II on the Polish issue and raised the question of granting Poland broad autonomy. Rapprochement with Germany enabled Russia to attain its most important foreign policy objective: abrogation of the restrictive clauses of the Peace of Paris.