Preet Bharara, a Democrat who was sacked as federal prosecutor by the Trump administration, suggested "truth isn't truth" would not sound convincing in a trial.
The exchange on Meet the Press on Sunday began with Mr Todd asking Mr Giuliani whether the Trump team was stalling about a possible testimony at the inquiry led by Special Counsel Robert Mueller into alleged meddling by Russian Federation in the 2016 U.S. election.
No one says it quite like Rudy Giuliani.
Donald Trump's personal lawyer has come out with a statement which may explain some of his client's outbursts: 'Truth isn't truth'. "You just said 'truth isn't truth!' That's not acceptable from a president's lawyer".
Following the backlash, Giuliani has since attempted to clarify his remark, citing that it wasn't "meant as a pontification on moral theology".
Trump says he allowed McGahn and others to testify.More news: Pentagon Announces Military Parade Will Be Postponed Until Next Year
"I'm not going to be rushed into having him testify so can he can be trapped into perjury", Giuliani said. It's especially risky to try to tell the truth to a federal officer since lying to one is a criminal offense; make an honest mistake in remembering details and you might get indicted depending upon how material that mistake is.
Giuliani, however, said Comey was let go for refusing to say Trump was not the target of the investigation - even though Comey and Trump both agreed he did so privately on multiple occasions.
Dean was White House counsel for President Richard Nixon during Watergate.
Although Trump has insisted he would cooperate with Mueller and field questions from his team of investigators, the president's own legal counsel has reportedly been less keen on the idea. "Not the truth", Giuliani said.
I think it's fair to say, as Stephen Hayes does, that it's unlikely that Mueller would try to indict the sitting president of the United States for "lying" to federal officials just because his account of a conversation didn't match up with James Comey's.
The comments by the former New York City mayor and Trump attorney caused host Chuck Todd to put his hand on his head and warn that the phrase would become a "bad meme".