ATCHISON, Kan. — In a state with a presidential library, a presidential loser's library and a gallery of Oval Office wannabes, add what's being billed as the "world's smallest presidential library."

Actually, it will be as much a presidential library as some say David Rice Atchison really was president for a day in 1849.

But it's something the Atchison County Historical Society Museum plans to open Feb. 20 — President's Day — using the presidential story to attract visitors to a larger view of the man for whom this Missouri River town is named.

"It's our hook to get people in, and hopefully they will learn something about this man," Chris Taylor, the society's executive director, said.

They'll learn that Atchison was pro-slavery but still a well-respected U.S. senator from Missouri and that his supporters founded this community and named it for him. Atchison was also a major player behind the 1854 Kansas-Nebraska Act that allowed voters to bring Kansas into the union as a free state. He often is portrayed as a Border Ruffian during the violent Bleeding Kansas period leading up to the Civil War.

Atchison became a senator in 1843 at age 36 and served until 1855. He was Senate president pro tem most of that time, including 1849. Whether he ever was president has been debated for decades. James K. Polk's term expired at noon March 4, when the next president normally would have been sworn in. However, March 4 was a Sunday, so Zachary Taylor waited until the next day to take the oath.

William E. Parrish, author of the only Atchison biography, sees more myth than reality to the story.

"It's a nice story, and I like the story, but he wasn't president for a day," said Parrish, a history professor emeritus at Mississippi State University.

He said Atchison's Senate term ended with the adjournment of Congress at midnight March 3, and he wasn't sworn in as a senator and elected president pro tem by colleagues until March 5.

"You could say he was president for a day, but his term as senator expired along with that of the old president," he said. "So, technically, he was out of office, too. But that doesn't make for as good of a story."

Parrish said Atchison told a reporter years later that he slept most of that Sunday and felt there was no president that day.

"If Atchison was right, it probably got started as a joke among the senators," he said.

Others, including the historical society director, maintain that Atchison probably was president.