You ask that Mr. Taft shall "let the world know what his religious belief is." This is purely his own private concern; it is a matter between him and his Maker, a matter for his own conscience; and to require it to be made public under penalty of political discrimination is to negative the first principles of our Government, which guarantee complete religious liberty, and the right to each to act in religious affairs as his own conscience dictates. Mr. Taft never asked my advice in the matter, but if he had asked it, I should have emphatically advised him against thus stating publicly his religious belief. The demand for a statement of a candidate’s religious belief can have no meaning except that there may be discrimination for or against him because of that belief. Discrimination against the holder of one faith means retaliatory discrimination against men of other faiths. The inevitable result of entering upon such a practice would be an abandonment of our real freedom of conscience and a reversion to the dreadful conditions of religious dissension which in so many lands have proved fatal to true liberty, to true religion, and to all advance in civilization.

    Letter to Mr. J.C. Martin concerning religion and politics (6 November 1908)