WASHINGTON (AP) — President Donald Trump faces a critical challenge in grappling with the new coronavirus outbreak: Asking Americans to believe him after he and top advisers have contradicted federal scientists in playing down the threat.

The stakes could be enormous from a public health and economic perspective, and also for Trump's personal credibility.

As Americans prepare for what experts say is an inevitable outbreak in the U.S., the X-factor may be an unpredictable president who has clashed repeatedly with scientists in his own administration and tends to see any crisis through the lens...