The Hindu–German Conspiracy Trial commenced in the District Court in San Francisco on November 12, 1917 following the uncovering of the Hindu–German Conspiracy (also known as the Indo German plot) for initiating a revolt in India. It was part of a wave of such incidents which took place in the United States after America's entrance into World War I.
In May 1917, eight Indian nationalists of the Ghadar Party were indicted by a federal grand jury on a charge of conspiracy to form a military enterprise against the United Kingdom. The trial lasted from November 20, 1917 to April 24, 1918. The British authorities hoped that the conviction of the Indians would result in their deportation from the United States back to India. However, strong public support in favor of the Indians meant that the U.S. Department of Justice chose not to do so.
From 1915 to 1917, the British government repeatedly requested that the United States government suppress the activities of Ghadar Party in the USA. However, these requests were turned down, as nothing in U.S. law prevented the Indians from seeking to overthrow the British government. The British ambassador, Cecil Spring Rice, was reluctant to press the matter diplomatically, fearing the political fallout at a time when Britain was working to end US neutrality and bring it into the war on the side of the Allies. Shortly before the outbreak of World War I, the Ghadar intellectual, Lala Hardayal, was arrested for anarchist activities and left the U.S. before he could be deported. With other Indian Nationalists in Europe, he enlisted the aid of Germany, who believed supporting a revolt in India would weaken the United Kingdom. In 1915, Germany offered the Indian Nationalists financial aid for transporting arms and Indians back to India via the United States.
The British government claimed that the United States was violating its neutrality with Britain by allowing Germany to conspire with the Indians on American soil. The first of several arrests of the Indian Nationalists were made in the Spring of 1917 with one hundred and five people of various nationalities being arrested. Eventually, thirty-five were tried for conspiracy, including nine Germans, nine Americans, and seventeen Indians.
During the war, nativists in the United States were expressing hostility toward certain minority groups, especially radicals and recent immigrants viewing anything un-American with suspicion. By 1917, Germans were the object of much of the American nativistic fervor. Fear of German subversion and conspiracies ran rampant throughout the U.S. after the Black Tom explosion and the Kingsland Explosion, both suspected to have been caused by German agents. Thus by being linked to Germany in a conspiracy, the Indian Nationalists should have been the recipients of the same hostility. Although calls for their deportation were made by government officials after the Hindu-German conspiracy trial, none of the Indian Nationalists were deported.