On the 75th anniversary of the atomic bombing of Hiroshima, during the 2020 U.S. presidential campaign, Joe Biden pledged to “restore American leadership on arms control and nonproliferation…and work to bring us closer to a world without nuclear weapons.” This month’s summit of the Group of Seven (G7) in Hiroshima, the site of the first atomic attack that killed more than 140,000 men, women, and children in 1945, provides President Biden with a historic and timely opportunity to do so. To support America’s Japanese allies, Biden and the other leaders will need to acknowledge the horrors of...