In the intervening time, Giuliani puts Trump's political opponents in a Giuliani's unique role in Trump's loose inner circle: both public advocate and provocateur.
floating theories and schemes designed to be and doubt about the truth, all in the service of Trump's own interests. It was a showcase for Giuliani's freelance, catch-as-catch-can approach to a trump attack dog.
Why what Giuliani is going to Ukraine? Democratic candidate Joe Biden, and looking into whether Ukrainians worked with Democrats to prompt the FBI investigation into Trump's former campaign chair, Paul Manafort.
Why did Giuliani cancel his trip? He told CNN on Saturday that "the meeting would have accomplished little and may be in the hands of those who might misrepresent it." He complained throughout the 24-hour period that the media refused to cover his version of events and that he contributed to his decision to cut the trip short.
They pointed back to Giuliani and the Biden-Ukraine story in general.
"It's great to see all these strong." "The Biden campaign official told CNN."
Changing his story 
One hallmark of Giuliani's work for Trump is his shifting explanations, which can make his story difficult.
"I stopped working on it a month ago, but I'm not working on it anymore." "He said."
Giuliani produced no evidence beyond the former vice president. He also continued to urge the Justice Department to conduct his own investigation into Biden.
"If he's not guilty or it's not provable, they should get out of the way now," Giuliani told CNN last week.
Just ask questions
But there's plenty to suggest Giuliani is more interested in raising the potential issue of Biden's wrongdoing than providing evidence for it. CNN transcripts of his interviews with Ukrainian officials and documentation he says the Ukrainians were investigating the younger Biden and his company in 2016, Giuliani declined.
He also said he would not speak to Giuliani about his lawyer's plans to go to Kiev, which Giuliani would cut short a few hours later, but that's interesting in the trip.
"I will speak to him I'm just curious about that, "Trump said, adding he has" not spoken to (Giuliani) at any great length. "
Whether he was chastised by the President, scared off in the first place, Giuliani will not say. CNN's Arlette Saenz contributed to this report.
CNN's Arlette Saenz contributed to this report.