William Brangham:

The accusation comes from Carlo Maria Vigano, the former senior Vatican diplomat to the U.S. In an 11-page letter released this weekend, Vigano claims Pope Francis knew several years ago, and ignored allegations against the former Washington, D.C., archbishop, Cardinal Theodore McCarrick.

McCarrick was accused of sexually harassing and abusing young adult seminarians, as well as sexually abusing two boys decades ago. McCarrick resigned last month.

In his letter, which offered no evidence for the accusation about the pontiff, Vigano urged Pope Francis to step down.

Yesterday, in response, Francis told reporters to read the document carefully and judge it for themselves.

Joining me now is Dennis Coday, an editor for The National Catholic Reporter.

Dennis, thank you for being here.

I wonder if we could just start with, this is a very serious allegation made by the former ambassador from the Vatican. How seriously should we take this?