On May 21, 1956, Democratic presidential candidates Adlai Stevenson and Estes Kefauver faced off in a one-on-one debate in Miami, Florida—the first televised primary debate.

Stevenson, who clinched the party’s nomination in 1952, would again secure the top spot on the Democratic ticket in 1956 and tap Kefauver as his running mate.

Photo: Abraham Lincoln Presidential Library and Museum