Ken Burns on why he fell in love with TR and FDR, and what the presidential cousins would make of our own political moment.

After binge-watching Ken Burns’ latest 14-hour documentary on the Roosevelts, I moved through the world at its deliberate pace. I was scheduled to meet Burns for breakfast and panned across the restaurant looking for him the way his camera helps you find a young FDR in a Harvard group photo. A trusted narrator in my head described the scene, accompanied by a piano. I expected David McCullough would be letting us know about the specials on the menu.

The pace quickened upon contact. Ken Burns is not like a Ken Burns film. He is fast-moving and speaks in riffs, nearly the linguistic opposite of his carefully constructed documentaries. Over 45 minutes our conversation touched on Harry Potter, the shooting in Ferguson, Vietnam, the Affordable Care Act, money in politics, shredded attention, restraint, the press, Mitch McConnell, Tolstoy, Ecclesiastes, steroids in baseball, the missing Malaysian airliner, and the nature of art.

And yet we still had time for the crowded lives of Teddy, Franklin, and Eleanor Roosevelt, and the more than 100 years of American history contained in The Roosevelts (airing at 8 p.m. Eastern on PBS from Sept. 14 to 20), which Burns spent the last seven years shaping into a seven-part narrative. It is three stories interwoven: the American story of rapid industrial and cultural change from the Progressive Era through World War II, the political story of two men who shaped the modern presidency, and the personal story of three towering figures full of wounds and failures and triumphs.

Despite the range of subjects we covered, our conversation was mostly about pace. Burns is in a great hurry to get people to slow down. He would like them to watch 14-hour documentaries, of course, but also to understand the complexity and tensions at the heart of history. It makes for more meaningful lives, he believes, and a better understanding of events, including the ones unfolding before us in the present...