Joe Biden is calling for everyone in the United States to wear a mask, well into the fall. "Every single American should be wearing a mask when they're outside for the next three months, at a minimum," Biden said Thursday afternoon in remarks in Wilmington, Del. "Every governor should mandate mandatory mask-wearing. The estimates by the experts are it will save over 40,000 lives." His comments came after a briefing on the coronavirus pandemic with his new running mate, Sen. Kamala Harris of California, and public health experts. … Biden has long been consistently wearing a mask and encouraging others to do so. But he's never been so explicit about mandates and a timeline.