first time that president trump raised biden's name with china. joining us now, jim sciutto who was part of the team that broke this story. jim, why don't you tell us what you learned? >> so along with my colleagues, we already knew that president trump mixed domestic politics with ukraine. we know the president mixed politics as well in u.s. interactions with china of course in the midst of consequential trade negotiations. bringing up both joe biden and elizabeth warren with the phone call in june of this year. and in addition at the same time, also bringing up those pro-democracy protests in hong kong. that he president trump would not mention those protests. a remarkable pledge to make for a u.s. government that normally is on the side of human rights in this kind of situation. you have him again bringing up