In the 1930s, a controversial Catholic priest called Father Charles Coughlin had a weekly radio programme with millions of listeners in the United States. As the decade wore on, Father Coughlin's views became so extreme and anti-Semitic that he was seen as a threat to national security by the White House. Simon Watts introduces recordings of Father Coughlin and talks to his biographer, Sheldon Marcus.PHOTO: Father Coughlin at the microphone (Associated Press)