President Biden travels to Hiroshima this week for a meeting of the G-7. 

While there, he plans to acknowledge the devastation wrought by the atomic bomb dropped on the city by U.S. forces, but the White House says he does not plan to make any apologies for America's actions during World War II.

Though 78 years have passed since the United States unleashed the power of the atomic bomb on Japan, the weapon continues to cast a shadow over geopolitics. And questions linger as to whether the call to bomb Hiroshima and Nagasaki was the right one. 

Could the war have ended without the use of these nuclear weapons? Could the U.S. have merely tested the bomb on a desert island as a show of force? And was it necessary to drop the second bomb on Nagasaki?

Historian and author Evan Thomas explores these questions in a new book titled, “The Road to Surrender.” In it, Thomas goes back in time to tell the story of the leaders grappling with the “morally fraught decisions” about whether to use their new weapon of mass destruction, and how to put an end to a brutal war.