Giuliani, who gained worldwide acclaim for his leadership as New York City's mayor during the September 11 attacks, argued that his work for Trump served a broader goal of protecting the office of the presidency.
Mr Trump's May 2017 firing of Mr Comey led to Mr Mueller's appointment as special counsel to oversee the federal investigation of Russian efforts to influence the 2016 presidential election and related matters.
For many months after Mueller's appointment past year, Trump avoided directly challenging the special counsel.
"The constitution gave the president the right to pardon himself", Mr Giuliani said, adding that Trump would not need to because "he didn't do anything wrong". The inconsistency will not faze them, since the willingness to spout nonsense is part of how they show their fealty to Trump. And one of the articles of impeachment prepared against President Richard Nixon in 1974 was for obstruction. "Pardoning other people is one thing - pardoning yourself is tough", ¬Giuliani told the US-based ABC.
To check whether Trump's assertion - which if true would essentially render him above the law - DW asked two legal scholars with expertise on constitutional power and the presidency to weigh in on the president's far-reaching claim.
"The Office of the President is not a get-out-of-jail free card for lawless behavior", the lawyers wrote. They want to just keep the pressure on him...
I know this sentiment has been used a lot since Trump took office, but I legitimately think it applies now: we've reached a new low in the Trump administration.
"I'm very surprised that this President would talk about pardoning himself", Corker, a retiring Republican from Tennessee, told CNN.
Giuliani, however, said he did not think his work for Trump would hurt his legacy, and argued it served a broader goal of protecting the office of the presidency.
The dispute among scholars on the issue nearly guarantees that if Trump faced indictment and pardoned himself, the next step would be a court challenge, with the President's fate decided by judges - or even the Supreme Court.
Now Kalt thinks people are eschewing the legal arguments because most people only care if Trump wins or loses. "I agree this raises questions about impartiality, but then again, in America, nobody sees prosecutors as being independent and impartial... they're out to win".