RAYNER, ISIDOR (1850–1912), U.S. lawyer and politician. Rayner was born in Baltimore, where his Bavarian immigrant father William Solomon Rayner had been one of the founders of the Har Sinai Congregation. He studied law at the University of Virginia and was admitted to the Baltimore bar in 1870. After several years of legal practice he entered Democratic Party politics and was elected to the Maryland state legislature in 1878 and to the state senate in 1885. In 1886 he was elected to the first of three terms in the U.S. House of Representatives, and after serving a term as Maryland attorney general (1899–1903), he was elected to the U.S. Senate in 1904 and again in 1910. Politically, Rayner was a moderate liberal. While still in the state legislature, he was a vigorous opponent of black disenfranchisement laws and Jim Crow, and his 1904 senatorial campaign was undertaken in defiance of the corrupt Democratic machine. In the Senate Rayner was particularly active on the Foreign Relations Committee, which he used as a forum to eloquently criticize President Theodore Roosevelt's imperialist policies toward Latin America. He also helped lead successful Senate efforts to abrogate the treaty with Russia in 1911 in protest against czarist antisemitism and discrimination against U.S. Jewish travelers. A nominal member of his father's congregation, Rayner married a Christian and was buried in a Unitarian ceremony.