Robert Mueller has subpoenaed Steve Bannon to testify in front of a grand jury as part of the Trump-Russia investigation, reports the New York Times.

Why it matters: "The move marked the first time Mr. Mueller is known to have used a grand jury subpoena to seek information from a member of Mr. Trump’s inner circle.” Last week, it was revealed that Bannon called Donald Trump Jr.'s 2016 meeting with Russians over dirt on Hillary Clinton "treasonous" in Michael Wolff's new book.