"The government of the United States is not, in any sense, founded on the Christian religion." -- George Washington (From the Treaty of Tripoli).
"I am tolerant of all creeds. Yet if any sect suffered itself to be used for political objects I would meet it by political opposition. In my view church and state should be separate, not only in form, but fact. Religion and politics should not be mingled." -- Millard Fillmore
[L]eave the matter of religious teaching to the family altar, the church, and the private school, supported entirely by private contribution. Keep church and state forever separate." -- Ulysses S. Grant
"I could not do otherwise without transcending the limits prescribed by the Constitution for the President and without feeling that I might in some degree disturb the security which religion nowadays enjoys in this county in its complete separation from the political concerns of the General Government." -- Andrew Jackson (In his refusal to establish a national day of prayer).
"There is not a shadow of right on the general goverment to intermeddle with religion. Its least interference with it would be a most flagrant usurpation. I can appeal to my uniform conduct on this subject that I have warmly supported religious freedom." -- James Madison
"I hold that in this country there must be complete severance of Church and State; that public moneys shall not be used for the purpose of advancing any particular creed; and therefore that the public schools shall be non-sectarian and no public moneys appropriated for sectarian schools." -- Theodore Roosevelt