Karl Paul Reinhold Niebuhr (1892–1971) was an American Reformed theologian, ethicist, commentator on politics and public affairs, and professor at Union Theological Seminary for more than 30 years. Niebuhr was one of America's leading public intellectuals for several decades of the 20th century and received the Presidential Medal of Freedom in 1964. A public theologian, he wrote and spoke frequently about the intersection of religion, politics, and public policy, with his most influential books including Moral Man and Immoral Society and The Nature and Destiny of Man.

The Evangelical Synod of North America (ESNA), before 1927 German Evangelical Synod of North America, was a Protestant Christian denomination in the United States existing from the mid-19th century until its 1934 merger with the Reformed Church in the United States to form the Evangelical and Reformed Church. This church merged with the Congregational Christian Churches in 1957 to create the United Church of Christ.