 Although protecting powers have existed in diplomatic usage since the 16th century, the modern institution of protecting power originated in the Franco-Prussian War of 1870–1871.All of the belligerents appointed protecting powers, necessitated by the expulsion of diplomats and placing of restrictions on enemy aliens.The United States acted as protecting power for the North German Confederation and several of the smaller German states, while Switzerland was the protecting power for Baden and Bavaria, and Russia for Württemberg.