Transcript for Stunning reversal on collusion between Russia and campaign

Overnight, some stunning words from the president's personal attorney, Rudy Giuliani. What he said about the trump campaign, the Russians and collusion. Did he change his argument suddenly? Here's ABC's chief white house correspondent Jonathan Karl. Reporter: The president and his legal team have long denied any collusion between the Russians and the trump campaign, but now this from the president's top lawyer, Rudy Giuliani. I never said there was no collusion between the campaign, or between people in the campaign. Yes, you have. I have not. I said the president of the United States. Reporter: No. In fact, he did previously deny any collusion between the Russians and the campaign. Is it still the position of you and your client that there was no collusion with the Russians whatsoever on behalf of the trump campaign? Correct. Reporter: And, of course, the president has denied it over and over again. There was no collusion at all. There was no collusion at all. Everybody knows it. Reporter: But now, the president's lawyer is saying the president was only speaking about himself personally. He said he didn't. He didn't say nobody. How would you know that nobody in your campaign -- He actually did say that, Rudy. Reporter: The president has in fact, tweeted, "Russian collusion with the trump campaign is a total hoax." There is no collusion between certainly myself and my campaign, but I can always speak for myself and the Russians, zero. Reporter: Tonight, in an attempt to clarify, Giuliani insists he hasn't changed his tune on collusion, but he sure seems to have narrowed the definition. "The point is, I represent the president, not the campaign," he tweeted. "But from both perspectives, there is no involvement in collusion with Russians on the e-mail hack, the only possible crime." Jon Karl live at the white house tonight covering all of this. And Jon, news tonight from president trump's former lawyer and fixer Michael Cohen, as well. It appears that he paid to rig online polls to try to boost Donald Trump's standing before he launched his campaign? Reporter: He is admitting that he paid to rig those polls. Before he announced his campaign, Michael Cohen, in a tweet earlier today, saying "What I did was at the direction of and for the sole benefit of Donald Trump." And David, he says, "I fruitly regret my blind loyalty to a man who doesn't deserve it." Jon Karl with us again tonight. Thank you, Jon.

This transcript has been automatically generated and may not be 100% accurate.