Historian and speechwriter Jeff Shesol, author of the new book “Mercury Rising: John Glenn, John Kennedy, and the New Battleground of the Cold War,” speaks with us about how the space race of the 1950s and ’60s differs from the space flights of Jeff Bezos and Richard Branson happening today, the unresolved questions that fuel power struggles in America, and why the pandemic and the climate crisis are crucial tests of the durability of the country’s democratic system.