GIULIANI: "And the Southern District says you can get out of jail if you do this, you've got three years now. There's a real motivation to sing like crazy. He's got to do a lot of singing to get out of the three years and he will say whatever he has to say. He's changed his story four or five times."

STEPHANOPOULOS: "So has the President."
GIULIANI: "The President's not under oath. And the President tried to do the best he can to remember what happened back at a time when he was the busiest man in the world."
This doesn't work on so many levels.
Let's start with the fact that Giuliani is admitting that Trump lied. Repeatedly. And that it's all OK because he wasn't under oath. Uh, what? This is the President of the United States we are talking about. Making a legalistic argument -- he didn't lie when there was a criminal penalty for doing so! -- isn't exactly a good pushback on the idea that Trump has a problem telling the truth.
Think of it this way: Giuliani is, in essence, arguing that Trump's lies don't matter because he didn't say them under oath. And that, presumably, if/when he was under oath, Trump would tell the truth -- and that truth would be different than all of the false things he has said publicly.
Which is, um, a remarkable thing.