There, for two crucial weeks in late February and early March, powerful Fox hosts talked about the “real” story of the coronavirus: It was a Democratic- and media-led plot against President Donald J. Trump. Hosts and guests, speaking to Fox’s predominately elderly audience, repeatedly played down the threat of what would soon become a deadly pandemic.

The person who could have stopped the flow of misinformation was Ms. Scott’s boss, Lachlan Murdoch, the chief executive of the Fox Corporation. But he wasn’t paying much attention. The 48-year-old heir to his family’s media fortune was focused instead on buying a streaming company called Tubi for $440 million, a person who has spoken to him said. The acquisition would drive “long-term growth,” he proudly announced in a news release on March 17…

Fox failed its viewers and the broader public in ways both revealing and potentially lethal. In particular, Lachlan Murdoch failed to pry its most important voices away from their embrace of the president’s early line: that the virus was not a big threat in the United States.