As Americans commemorate the 400th anniversary of the 1620 Plymouth landing and sit down for Thanksgiving dinner, many are bound to be reminded that "one should not mix religion and politics." But the most important episodes of American history do not reflect any type of adherence to this oft-repeated, friendly advice. From America’s colonial beginnings to the latest political developments, honest observers will find that religion has played, and continues to play, an active part in establishing and maintaining our experiment with republican government. History professor Richard Carwardine stands as one of the most authoritative scholars on the role of faith in the American story. Carwardine's impressive career includes being a Rhodes Professor of American History and Institutions at Oxford University, winning the 2004 Lincoln Prize for Lincoln: A Life of Purpose and Power, and serving as president of Oxford's Corpus Christi College. I recently interviewed the Welsh historian to get a transatlantic view on how faith shaped the American political landscape during the mid-1800s.