WASHINGTON (AP) — For most Americans alive today, the idea of a shared national sacrifice is a collective abstraction. It’s a memory passed on from a grandparent or through a book or movie. Not since World War II, when people carried ration books, has the nation been asked to truly sacrifice for a greater good. Now, with the coronavirus, it’s as though a natural disaster has taken place in multiple places at once. Will America step up as it enters what one prominent historian calls “a new moment”?