The first Christadelphians and politics

In an earlier post I noted how the name 'Christadelphian' was coined by John Thomas and first used in Ogle County, Illinois, in order to claim exemption from military service for Samuel Coffman and his family and others on the grounds of being members of a denomination with a conscientious objection to military service.

As they were the first to use the name 'Christadelphian' the Coffman's were, strictly speaking, the first Christadelphians.

The following information comes from the "Ogle Co. Portrait and Biographical Album" (Chapman Bros., Chicago, IL, 1886). John Coffman, son of Samuel Coffman, was a Justice of the Peace and Notary Public of Baileyville. The Ogle Co. Portrait and Biographical Album says of him that he was "one of the most progressive and prosperous citizens in the area" and goes on to say that "he is an active worker in public affairs and a zealous Republican in politics. He is also a member of the Christadelphian Church to which he gives his hearty support both in offerings and by his presence and labors" (my emphasis).

It seems the Coffman family generally may have been zealous Republicans. In a biographical note on Addison Coffman (another son of Samuel Coffman) in the "Biographical Record of Ogle Co." (S. J. Clarke Publishing Co., Chicago, IL, 1899) we read "Since casting his first presidential vote for Abraham Lincoln, in 1864, Mr. Coffman has been a stalwart supporter of the Republican party, but he has never cared for office, though he has served for three years as commissioner of highways. He is one of the leading and popular citizens of his community and wherever known he is held in high regard."

It's interesting that in the same year in which the Christadelphian denomination was born the first Christadelphians were actively involved in politics, supporting the Republican party and voting for Abraham Lincoln. This is especially interesting in view of the fact that later Christadelphians boasted that the denomination was "entirely unpolitical", and some ecclesias outlawed participation in politics (including voting). At what stage, I wonder, did Christadelphians shift from being stalwart and zealous supporters of political parties, actively involved in public affairs, to being "entirely unpolitical"? And why?