WASHINGTON (AP) — The U.S. surgeon general is raising the specter of the gravest attacks against the nation in memory, 9/11 and Pearl Harbor, to steel anxious Americans for impending sorrow in the age of the coronavirus. And the government’s top infectious disease expert is urging vigilant preparation for a virus that’s unlikely to be wiped out entirely in the short term and may emerge again in a new season. Yet both President Donald Trump and Vice President Mike Pence are striking optimistic tones, telling reporters during a Sunday evening briefing that hard weeks ahead will ultimately lead to the nation beginning to turn a corner as it fights the virus.