A "truther" is somebody that confuses nutters, rightwingers, republicans, Hannity, Beck, O'Rielly FOX News pundits etc., by telling them the truth. Such is their nature when telling them the truth and rebutting their lies.
President Bush had a blank confused look on his face when a truther told him there were no WMD's in Iraq.
Christianism is a political ideology derived from the conservative religious views of Christian fundamentalism. It holds Christianity is not only a religion, but also a political system that governs the legal, economic and social imperatives of the state.
It would seem Christianism is the dominant theme of the Republican party base.