Who Was The First Truly Christian President?

It's a good question after Saturday night's pander-thon to Rick Warren. If you define Christian as the evangelical magazine Christianity Today does, the answer is probably Andrew Jackson. Here's CT's intellectually honest terminology:

George Washington 1789-97 Episcopalian (theistic rationalist*)

John Adams 1797-1801 Congregationalist; Unitarian
Thomas Jefferson 1801-09 Episcopalian (theistic rationalist*)
James Madison 1809-17  Episcopalian (theistic rationalist*)
James Monroe 1817-25 Episcopalian (deist?)
John Quincy Adams  1825-29 Unitarian
Andrew Jackson 1829-37 Presbyterian

CT describes "theistic rationalism" thus:

theistic rationalists believed that God was active in the world and that prayer was therefore effectual. They contended that religion's primary role was to promote morality, which was indispensable to society.

When the theocons talk of American politics being imbued with religion from its founding, they have a point. But the type of religion that influenced the Founding Fathers could not be further removed from the deeply personal, evangelical experience touted by Warren, and its relationship to divine truth far more reserved than contemporary fundamentalism. By today's standards, many of the founders would be termed secular humanists with Christian leanings who nonetheless believed religion to be essential to social order.

One question: has any presidential debate been held in an active church before?