Transcript for Letter to Mueller from Trump lawyers says president cannot be guilty of obstruction

To politics now. And president Trump's personal attorney Rudy Giuliani cry peanut attention with special counsel Robert Mueller. Giuliani telling ABC news overnight that if Mueller tries to subpoena the president he will fight it in court. And this comes as we're learning about a secret memo from Trump's lawyers with some eye opening revelations about their legal strategy so let's go to White House correspondent terror on Larry. Tara good morning. Good morning again Hollowell Giuliani certainly seems to be taking it up a notch. He said even a letter was sent about five months ago the legal strategy is still the same and it's based on a very broad interpretation of the powers of the presidency. Overnight. The president's lawyer Rudy Giuliani turning up the heat on special counsel Robert Mueller telling ABC news is Mueller tried to subpoena asked were going to court. This new threat comes as a shocking secret letter written by president terms legal team leaked to the New York Times. The twenty page memo making broad claims that the president not be guilty of obstruction in the Russia collegiate investigation. Or be subpoenaed to speak to Muller. The Russian collusion hoax to hoax it's a Democrat hoax really a hope. The memo delivered in January remains a road map for chumps legal strategy. In it the lawyers argue that's quote the chief law enforcement officer that would amount to him obstructing himself. They also had a charm has the power to quote terminate the inquiry or even exercise his power to pardon. The letter questioning why Mueller even need to sit down with the president considering the documents they've handed over writing quote. In light of these voluntary offerings your office clearly lacks the requisite need to personally airy the president. That's why this is a rape investigation the amount of government misconduct is accumulating this is not good for the American people. Giuliani confirmed the contents of that letter to ABC news even though he was not a member of the legal team at the time forty minutes before the New York's times story published the president blaming the Justice Department and the special counsel for the leak. Tweeting when all is very expensive witch hunt hoax ever and so bad for our country. Is a special counsel Justice Department leaking my lawyer's letters to the fake news media. There's no evidence of who leaked the letter but Giuliani said that there should be an investigation into the leak. He's using this as just another talking point in their war against Robert Mahler fan Paula. Tariff on Larry thank you very much great reporting we appreciate it let's bring in ABC news chief hacker George Stephanopoulos is going to be hosting this week a little and that's under good morning sir so you've got Rudy Giuliani on the show this morning if he's right that the president plans to fight this subpoena is that a fight he's likely to win. Well the precise question has never been adjudicated by the Supreme Court but other presidents have been subpoena returning to a subpoena for those tapes back in 1974 he had turned them over. Bill Clinton was subpoena back in 1998. It he avoided of this this serving of that subpoena by agreeing finally to do some grand jury testimony. By remote for hours with Ken Starr are the president's had been subpoenaed other presidents have complied. But this exact question whether president can be forced to personally testify. Has never been tested by the courts. And it seems pretty clear the regional and wants to fight if it comes to that but that delay it could delay indicates is that good or bad for the White House that's a good question I don't know could take months he could take even years for to go all the way through the courts that we know of since this letter was written back. In January that actually Robert Mueller has been ready to talk to the president for quite some time has been the president's team it's been resisting. It was great reporting by terror primary this morning's of those talk about the secret memo that was leaked from tribes legal team which says that the president cannot obstruct justice. Because he's the president is at argument likely to win. It's it's it's really a breathtaking. Argument what they argue in this memo is that the present Nazis because he's a chief. Law enforcement officer can terminate any federal investigation is it any time for any reason. It's hard for me to imagine. That the courts would uphold that that suggested the presence completely above the line and think about. The hypothetical let's say there was evidence that the president. Murdered his ballet. Are they saying the president could terminate that investigation. Pretty remarkable stuff issues if there's an innocence anchorman gray area right now that we have to explore as well. Well let's and it's a question whether it's fair is never contested area by the courts but it is a pretty sweeping assertion. Other negative. Our thank you George a lot to discuss thank you start his morning we're always appreciate having you here I want to remind everybody your it has always has a big show this morning as his eyes and no one out walk when the president trumped personal attorney Rudy Giuliani. Plus he will have the latest analysis on the revised US North Korea summit that is coming up I'm this week right here any BC George thank you again.

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