New whistleblower could blow up Trump's main argument

A dramatic new development could threaten one of President Trump’s defenses in the House impeachment inquiry. A second whistleblower has come forward, claiming to have firsthand knowledge of the president's July 25 phone call with the president of Ukraine. A lawyer for the new whistleblower said the person made a "protected disclosure and cannot be retaliated against." The president brushed it off on Twitter, saying "keep them coming." Weijia Jiang reports.