Over the weekend, reports of a secret whistle-blower complaint against President Trump turned into allegations that the president had courted foreign interference from Ukraine to hurt a leading Democratic rival, former Vice President Joseph R. Biden Jr. Mr. Trump called the allegations a “witch hunt” and accused Mr. Biden of corruption.

Guest: Michael S. Schmidt, who covers national security and federal investigations for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.

Background reading:

• President Trump acknowledged that he discussed Mr. Biden during a phone call with Ukraine’s president, but he did not directly confirm news reports that he had pressured the foreign leader for an investigation.
• Here’s what we know about the role of Mr. Biden and his son Hunter in the controversy.