President For A Day On March 4, 1849, David Rice Atchison achieved the singular honor of being President of the United States for one day... or so some folks say. The story goes that Atchison, a Senator from Missouri who was President Pro Tem of the Senate took the reins when Zachary Taylor, a very religious man, refused to be inaugurated on March 4, because it was a Sunday. It's a dandy story that's, as you might expect, popular with Missourians and part of the Ripley's Believe It Or Not canon. But some historians say it's not quite true. NPR's Dean Olsher reports.