Why we’re still learning new things about the JFK assassination

It’s hard to believe there’s a new eyewitness account from a Secret Service agent who was right there at the assassination of John F. Kennedy.

This is, after all among the most investigated, revisited and argued about events in US history.

But Paul Landis, who in 1963 was a young agent detailed to protect the first lady, Jacqueline Kennedy, shares recollections in a new memoir, “The Final Witness,” to be published next month. The 60th anniversary of the assassination is in November.

What Landis remembers about being near Kennedy’s body...