Andrea Mitchell on Friday landed an exclusive interview with Chicago slumlord Valerie Jarrett to discuss terrorist threats against the United States, as well as the resignation of her close friend Attorney General Eric Holder. It was a very enlightening interview. “I have nothing new to report,” Jarrett said when asked about reported threats to U.S. subway systems. Mitchell asked about President Obama’s speech at the United Nations earlier this week. It was a very important speech, Jarrett said. “It was a very strong, powerful speech,” she said. “It was a very constructive and important week, and the speech sent a...