The current commemoration of the 50th anniversary of the assassination of President John F. Kennedy raises one lingering question: What explains JFK’s enduring hold on the national imagination?

Why does Kennedy figure so largely in American memory when his presidency was so short, his accomplishments so few (particularly in the domestic arena where he cannot compare with his successor) and his legacy transient?

So is our collective fascination with Kennedy just superficial — a product of the remarkably attractive, compellingly visual nature of his presidency?

After all, though presidents since William McKinley appeared on film and Dwight D. Eisenhower made brilliant use of the new medium of television, Kennedy truly became the first media president. His presidency remains primarily a series of images — from the hatless, apparently vigorous man at the lectern on Inauguration Day to the poignant photo of John F. Kennedy Jr. saluting his father’s casket 50 years ago this month.

Kennedy’s legacy, however, is more than a series of shallow images. His influence was not superficial. For JFK substantially altered the nature of political competition in the United States.