The faith names prejudices individually — racial, national, religious, class, and prejudice arising from differences of education — and treats them as the operative cause of conflict rather than as unfortunate attitudes attached to it. The American record is the sharpest test case and the faith's conduct in it was unusual for its period. 'Abdu'l-Bahá, touring the United States in 1912, called racial prejudice the most vital and challenging issue facing the country, refused to address segregated gatherings in Washington, seated a Black attendee at the head of a table at a luncheon given by a white host, and encouraged the marriage of Louis Gregory, a Black lawyer, and Louisa Mathew, a white Englishwoman, at a time when such marriages were criminal in most American states. Shoghi Effendi later addressed the American community at length on the subject in The Advent of Divine Justice, telling them the responsibility fell more heavily on the white members. The community's practice has not always matched the teaching, which Bahá'í writers themselves have documented.