Many new states entered the United States around 200 years ago, but only Missouri almost killed the nation it was trying to join.

When the House of Representatives passed the Tallmadge Amendment banning slavery from the prospective new state in February 1819, it set off a two-year political crisis in which growing northern anti-slavery sentiment confronted the aggressive westward expansion of the peculiar institution by southerners.

Historians Jeffrey L. Pasley and John Craig Hammond commemorate Missouri’s Bicentennial (August 10, 2021) with an examination of the events surrounding the state’s addition to the Union in a discussion.

They draw from both installments of their two-volume series, A Fire Bell in the Past: The Missouri Crisis at 200, the second of which is set to be published in December 2021.

Jeffrey L. Pasley is Professor of History and the Associate Director of the Kinder Institute on Constitutional Democracy at the University of Missouri.

John Craig Hammond is Associate Professor of History and Assistant Director of Academic Affairs at Penn State University–New Kensington.