You are entitled to know whether a man seeking your suffrages is a man of clean and upright life, honorable in all of his dealings with his fellows, and fit by qualification and purpose to do well in the great office for which he is a candidate ; but you are not entitled to know matters which lie purely between himself and his Maker. If it is proper or legitimate to oppose a man for being a Unitarian […] then it would be equally proper to support or oppose a man because of his views on justification by faith, or the method of administering the sacrament, or the gospel of salvation by works. If you once enter on such a career there is absolutely no limit at which you can legitimately stop.
Theodore Roosevelt (1858-1919) American politician, statesman, conservationist, writer, US President (1901-1909)
Letter to J. C. Martin (9 Nov 1908)
(Source)