In a year of deep political division, perhaps no issue has ignited partisan finger-pointing as much as the revelation in a new book co-authored by Washington Post reporters Bob Woodward and Bob Costa. According to the book, Joint Chiefs Chairman Mark Milley assured his counterpart in China that he would call in advance if President Donald Trump was “unhinged” enough to launch a nuclear attack.

The scenario appears to have its origins in a conversation that Speaker Nancy Pelosi had with Milley after the Capitol riots. Doug McKelway has more.