jim sciutto, what could i be missing, the day after the whistle-blower report that he's mentioned in, the special envoy to ukraine resigns? >> he's meant to be america's primary official dealing with ukraine affairs. in fact, we saw from the president's use of his own personal lawyer, rudy giuliani, that from the president's perspective, it appears he was using someone else outside of government. >> that's a key point. jim baker pick up on that. help us with the legalities. we saw the text from volcker to rudy giuliani. did rudy giuliani have to register as a foreign agent? when is it okay, if ever, for a private citizen to work with the state department this way? what are the legalities involved? >> well, so it's a bit tricky. let back up. generally speaking under the constitution the president does have authority to select what envoys or emissaries that he wants to engage with or have