In
Faith on the March, Macmillan described a private meeting he had with Russell in 1916. According to Macmillan, Russell spoke of his poor health and indicated a desire for Macmillan to take over the affairs of the Allegheny office. Russell died several weeks later, on October 31, 1916. By 1918,
The New York Times described Macmillan as "Superintendent of the Bethel Home" and as one of "the leaders of the International Bible Students Association". At the January 5, 1918, annual meeting of the Watch Tower Society, Macmillan was formally elected to the Society's board of directors, and Rutherford was reelected as a board member and president. That year, Macmillan—along with Rutherford and other Watch Tower Society officials—was arrested, charged with violation of the
Sedition Act of 1918 as a result of anti-war sentiments expressed in the book,
The Finished Mystery; they were sentenced to
federal prison in Atlanta, but were released and exonerated in 1919. During the 1920s, Macmillan traveled extensively on service tours to
Europe and the
Middle East, for public speaking engagements and to monitor activities at branch offices around the world. Such assignments included
Scotland,
Denmark,
Finland,
Norway,
Palestine,
Lebanon and
Syria,
Italy, and
Sweden. Macmillan also traveled throughout the United States and Canada as an appointed "pilgrim", performing twice-yearly visits with local congregations. By the 1930s, Macmillan, based in Brooklyn, was a "traveling representative" speaking at congregations and larger assemblies, encouraging individuals to pursue the full-time ministry. Macmillan also met with local
law enforcement and government officials to explain the significance of the dozens of then-recent
U.S. Supreme Court decisions which were mostly favorable to Jehovah's Witnesses. Macmillan was permitted by the director of the United States
Bureau of Prisons to regularly visit Witnesses in federal prisons in the United States who had been incarcerated for refusing military service during
World War II. ==Later years==