Transcript for 'Michael Cohen is on his own here,' but 'potentially has information': Dan Abrams

This week squeeze on just how Michael Collins knowledge of the president's past. Could determine trumps future and pound team trump is planning to fight back. ABC news learning of new efforts to pressure college including accusations that he is violated attorney client privilege. Trump attorney Rudy Giuliani is also attempting to discredit a recording of Trout. Discussing payments to a former Playboy model. Telling ABC news his team has hired multiple experts to review the tapes. Just a few months ago Giuliani publicly praised Cohen on this program. He doesn't have any. Incriminating evidence about the president or himself. The man is an honest honorable lawyer but now Giuliani is on the attack. She's back is up against the wall who who lie like crazy because he's a little as life what does history than just you've been lying under pressure. The president's attorney seeming to distance himself from Cohen now saying he did not know him very well. It all comes after that bombshell report about a 2016. Trump tower meeting between members of the trump campaign. And Russians who are expected to offer damaging information on Hillary Clinton. Trump has repeatedly denied knowing anything about it listen to what he said last year did you Euro. I. Who wanted Newman an amendment. But now sources tell ABC news that calling claims trump knew about the meaning in advance. If Cohen's claim proves true. If Donald Trump did in fact know about that meeting with the Russians does that mean an American presidential candidate. Considered accepting aid from the foreign adversary in an election. And then attempted to cover it up. If that's the case it could potentially define the Lawler investigation. By helping the special counsel build the case for collusion with Russia as well as obstruction of justice. Here now to a help explain what it all means and where things are headed. ABC news chief legal analyst Dan Abrams and former New Jersey governor and federal prosecutor Chris Christie and ABC news contributor. And Dan I want to start with you trump has officially severed the relationship with Cohen he was paying for Collins legal friend sharing information but no longer. His lawyer Rudy Giuliani telling ABC we wouldn't consider it in our best interest to share confidential information with them and they would feel the same way what is this all mean to you Dan. Well look the fact that there are now no longer sharing information is not a surprise this has been in the works for for many weeks it is clear now. A that Michael Coen is on his own here. It's also clear that he potentially has information. To provide to Robert Mueller the let's be clear. He's being investigated by the southern district of New York which is a separate entity investigating. Michael Coen. He doesn't have a deal right now. With the Robert Mueller. We don't know he's going to have a deal with Robert Mueller and as a result we don't know exactly what he's gonna offer to Robert Mueller. Plot. If he can provide what we are here which is this piece. That Donald Trump knew about the meeting. That does potentially become significant it's not going to define it I don't think you've got a lot of other potential witnesses here you've got. A lot of other people that they've made deals with who or even potentially more important than Michael Coen. But if your Donald Trump and your Rudy Giuliani and you know that Michael Coen is ready to make a deal it has to make you very nerve. Saying that Cohen has violated the attorney client privilege both publicly and privately. And is in grave jeopardy of being disbarred is he trying to shine a mop. Well this aren't sure that's part of the motivation for but you know Martha let's remember if you listen to your read it. There were four different gifts there. So part of what I think Dan is saying and I agree with them is that. We don't even know this is none of this information which came from one news report. Has even been stated by. Mr. Cohen or anybody. On his legal team. So we don't even know the information that were being given. By that other outlet is even accurate out now if it is in and week discusses before. Collusion. It's not a crime. And so the fact of the matter is that we're a long way away yet from having any thing talk about here. Cohen still has to make a deal and that deal is probably not going to be with Bob Mueller. That feels going to be with the southern district in New York where the people who were investigating him. For potential crimes in the ones who initiated the raid of his office and hotel room and home. So. And Dan is right we need to like everybody's take a step back here and there is a certain level of hysteria that goes along with the story. On the way it's reported. And quite frankly I don't think that what we know right now what we know merits that. But when. But if you read Martha the indictments of the Russians so far and I think that's really important. In connection with this you talk about what possible crimes could there be you do it the possibility in addition to any obstruction charge. Of conspiracy to defraud the United States which is say. A sort of big over reaching conspiracy charge. That Muller's team has already been using in connection. With the Russians that's a real legal danger on the question of the attorney client privilege. The Giuliani is talking about I don't know exactly what he's talking about meaning when it comes to the tape that we've heard about apparently Giuliani has waived attorney client privilege. On other conversations for example. This notion that may be Donald Trump knew about the meeting well apparently there were other people in the meeting if there were other people there there is no attorney client privilege it has to be a private conversation. Not just with someone who broadly is your attorney but he private conversation with someone who has been retained. For this matter so someone's your tax attorney for example. And you talked and that's something criminal it doesn't necessarily mean the attorney client privilege applies I don't really know exactly what he's talking. And Governor Christie I want to go back to these reports. Yeah if these reports are true and CNN specifically reported. That Cohen alleges that he was present along with several others if you were Robert Mahler and you heard those reports. What would you do about it. Well two things one. I I try to do the best I could to get to the bottom of where the reports came from. But secondly I can tell him more because is that as the US attorney I had to deal with deciding where these coal operators all the time or not in a particular matter. The fact that Cohen or someone like Colin behalf may be out there spewing out all this information into the public realm. What hurts the tape we're doubts this alleged report of about him being at a meeting. Does it wouldn't make me very comfort as a prosecutor that want this guy his legal team is as a as a part of team America. To be a witness. A case that was bringing. This is incredibly irresponsible stuff. To be out there it is not a Michael Collins best interest when he does not have a deal yet. As Dan noted and I think it would give me as a prosecutor a lot of concern before it made any deal with ours that the US attorney in the southern district. Or Robert Mueller. You're be a long come to Jesus meeting with Michael Cohen and with his attorneys about from this moment forward you have to deal. Keep your mouth shot. Because it doesn't help the prosecution to have all this information out there. And Dan just quickly if you can't let's look at the trump legal stat as strategy two months ago as we heard really Rudy Giuliani was calling Michael Cohen an honest honorable lawyer. And now he's saying he's been lying for years and president trump is bringing up that Cohen said that Don junior was an honest. Broker. Just last year what are they trying to do hair looked Robb. Is he trying to undermine cones credibility. And there is a real concern. About Michael Collins credibility I mean. He is under serious investigation for a wide variety of crimes in the FBI raided his office not to get information on Donald Trump it because there was evidence of a possible crime. And crimes by Michael cone. So he is not the would be ideal witness that you want which is why I say again. Anything he says they're gonna want corroborated they're gonna wanna be able to back it up with other witnesses and other evidence okay thanks very much.

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