On New Year's Day of 1802, the Baptist evangelist John Leland delivered a remarkable gift to the White House: a 1,235 block of cheese. Newspapers called it the "mammoth cheese." It came from Leland's village of Cheshire, Massachusetts, sent by evangelical Baptists of New England, to honor their beloved president, Thomas Jefferson. For those familiar with Jefferson's religious beliefs, the mammoth cheese is both a prodigy and a puzzle: why would devout Christians love this deistic skeptic so much? The answer to the puzzle of the mammoth cheese goes a long way toward explaining the role of faith in the era of the American Revolution. Americans incessantly debate the place of religion in their nation's founding. The controversy has resulted from court decisions that have progressively lessened expressions of faith from American public life and schools. Conservative Christians often argue that America was founded as a Christian nation, and that secularization betrays the country's roots and the intentions of the Founders. Secularists, conversely, argue that most of the leading Founders were Enlightenment-influenced rationalists, and that faith played no formative role in American independence from Britain. As I show in my book God of Liberty: A Religious History of the American Revolution, the relationship between John Leland and Thomas Jefferson offers a more accurate picture than does the polarized choice of either a wholly devout or wholly secular American Founding. There was real spiritual diversity among Americans in 1776; not as much as one sees today, to be sure, but there was a significant range of beliefs. Indeed, one would be hard pressed to find more sharply different faiths than those of Leland and Jefferson. Leland was an evangelical preacher of incredible endurance and commitment, who traveled America's byways telling thousands of listeners to put their faith in Jesus, the Son of God. Jefferson, by contrast, tried to keep his skepticism private, but in his retirement it became abundantly clear that Jefferson saw Jesus not as the Messiah, but only as a great moral teacher. For Jefferson, Jesus was not divine, and he did not rise from the dead. Jefferson even produced an edition of the Christian Gospels to this effect, with the miracles and resurrection of Christ literally snipped out with scissors. Given today's political and religious climate in America, you might assume that Leland and Jefferson would have loathed one another, but herein lies the surprise of the mammoth cheese: Leland and many evangelicals adored Jefferson, in spite of the president's reputed skepticism. They did so because Jefferson was, along with James Madison, America's greatest champion of religious liberty, writing Virginia's Bill for Establishing Religious Freedom, adopted in 1786 as a critical precedent to the U.S. Constitution's First Amendment guarantee of free exercise of religion and ban on a national established church. Many evangelicals, Baptists in particular, had suffered persecution during the colonial era under the established denominations; nowhere had they suffered more than in Virginia, where even in the early 1770s some Baptist preachers remained in jail for illegal preaching. Jefferson and Madison deplored this sort of persecution, and they agitated for religious liberty, with the support of many evangelicals. The cause of religious freedom made allies of deists and evangelicals. Did Jefferson envision a secular public sphere, as his liberal admirers might imagine today? Clues to Jefferson's intentions came the weekend that Leland delivered the mammoth cheese, a weekend, as it turns out, that was one of the most significant in America's history with regard to church-state relations. For this was when Jefferson sent his famous "wall of separation" letter to the Baptist Association of Danbury, Connecticut, an evangelical group of Baptists who, like Leland, admired Jefferson. In his letter, Jefferson reminded them of their common commitment to the principles enshrined in the First Amendment, which built a "wall of separation" between church and state. The evangelical New Englanders did not interpret "wall of separation" to mean rigid secularism, and indeed, neither did Jefferson. That Sunday, Jefferson attended a church service in the House of Representatives chambers, with John Leland giving the sermon. Whatever "wall of separation" meant to Jefferson, it could include holding church services in government buildings, a practice which Jefferson routinely allowed as president. This does not mean that Jefferson was personally devout, but that Jefferson was generously appreciative of the significance of faith in American public life. So yes, the leading Founding Fathers were a diverse lot with regard to faith, and some of them, including Jefferson and Benjamin Franklin, were deists. Franklin actually spoke of himself as a deist, yet he also urged the Constitutional Convention to open its meetings with prayer in 1787. So even the deists were not hostile to the supportive role of faith in America. That openness to religion helped forge the alliance between deists and evangelicals, an alliance that helped secure both the new American nation, and America's steadfast commitment to religious liberty.