The long answer involves the Abraham Lincoln/Stephen Douglas debates of 1858 and Wendell Willkie versus FDR in 1940, but the short answer is that in 1956 a University of Maryland student helped jump-start the modern era of debates.
Friedrich Kahn—born Fritz Kahn in Germany in 1932—proposed having the two presidential candidates face off against each other. Remarkably, this had never before happened. Democrats Adlai Stevenson and Estes Kefauver had engaged in a primary debate, but the two major-party candidates had never done so.
Kahn was an entrepreneurial sort. He had already survived the Holocaust in hiding, created a championship youth-soccer club in Brussels, and borrowed money to make it to America. He joined the US Army within a year of his arrival, and upon his discharge a lieutenant urged him to go to college.
While at Maryland, Kahn joined the university's International Club. Fluent in English, French, German, and Dutch, he became its vice president. In that capacity, he came up with the idea of inviting Stevenson and Republican President Dwight Eisenhower to campus and having them answer questions from students before the election.
In this quest, he sent queries to the Associated Press and United Press International as well as letters to Eleanor Roosevelt, Maryland governor Theodore McKeldin, and university president Wilson Elkins. Mrs. Roosevelt sent the idea to James Finnegan, head of the Stevenson campaign, and told Kahn that the debate "might be something that would arouse the interest of young people all over the country." Kahn was also interviewed by the Baltimore Sun—with the headline immigrant urges debate—and the story was picked up in papers nationwide.
Unfortunately for the country and political junkies everywhere, Maryland's Board of Regents put the kibosh on the idea on grounds that the campus shouldn't be used for political purposes. According to Kahn, the board—sensitive after a previous university president had used the campus to launch a gubernatorial run—forced the student association to rescind its invitations to Stevenson and Eisenhower.
The board later revoked the no-candidate rule, and presidential hopeful John F. Kennedy spoke on campus in 1960. Today most presidential debates are held on college campuses, including all four of this fall's scheduled showdowns.
In America's first presidential debates in 1960, Kennedy faced off four times against Republican Richard Nixon, meetings best known today for the positive visual impression JFK made and the contrast between the tanned, handsome Kennedy and the pale, unshaven Nixon.
Kahn, now 79 years old and living in Bethesda, says that after his foray into presidential debates he "went on with life," teaching at Howard University and getting a master's degree at Johns Hopkins School of Advanced International Studies. After Lyndon Johnson initiated the War on Poverty, Kahn went to work at the Executive Office of the President, setting up statistical systems for Job Corps centers and beginning a "good career" in government.